Schuylkill Technology Center / Homepage
[pic]
COURSE TITLE: Fundamentals of Control Circuitry
DUTY TITLE: Solid State and Digital Electronics
DUTY NUMBER: 2100
TASK # 32: Solid State and Digital Functions
PURPOSE: To Understand the Concept, Control, and Troubleshooting Techniques of the Various Types of Solid State and Digital Devices.
TASKS:
|2101 |Identify and explain electronic symbols shown on diagrams and schematics. |
|2102 |Describe and explain the function of diodes. |
|2103 |Explain the function of Zener diodes. |
|2104 |Explain the function of transistors. |
|2105 |Explain the function of power supplies. |
|2106 |Explain the function of filters. |
|2107 |Explain the function of half-wave, full wave and three-phase rectifiers. |
|2108 |Explain the function of thyristors. |
|2109 |Explain the function of single-phase and three-phase inverters. |
|2110 |Connect and operate alternating current and direct-current variable speed drives. |
|2111 |Troubleshoot alternating current and direct current variable speed drives. |
NOTE: This task is not on the current Program of Study Task Listing; however this is an important task the students must learn for the Electrical trade. The P.O.S. numbers shown are from a previous task listing.
REVISION: 2016
|ENGLISH LANGUAGE ARTS |
|CC.1.2.11-12.J Acquire and use accurately general academic and domain-specific words and phrases, sufficient for reading, writing, speaking, and |
|listening at the college and career readiness level; demonstrate independence in gathering vocabulary knowledge when considering a word or phrase |
|important to comprehension or expression |
|CC.1.3.11-12.I Determine or clarify the meaning of unknown and multiple-meaning words and phrases based on grade level reading and content, |
|choosing flexibly from a range of strategies and tools. |
|MATH |
|CC.2.1.HS.F.4 Use units as a way to understand problems and to guide the solution of multi-step problems. |
|CC.2.1.HS.F.6 Extend the knowledge of arithmetic operations and apply to complex numbers. |
|READING IN SCIENCE & TECHNOLOGY |
|CC.3.5.11-12.B. Determine the central ideas or conclusions of a text; summarize complex concepts, processes, or information presented in a text by |
|paraphrasing them in simpler but still accurate terms. |
|CC.3.5.11-12.C. Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; |
|analyze the specific results based on explanations in the text. |
|WRITING IN SCIENCE & TECHNOLOGY |
|CC.3.6.11-12.E. Use technology, including the Internet, to produce, publish, and update individual or shared writing products in response to |
|ongoing feedback, including new arguments or information. |
|CC.3.6.11-12.F. Conduct short as well as more sustained research projects to answer a question (including a self generated question) or solve a |
|problem; narrow or broaden the inquiry when appropriate; synthesize multiple sources on the subject, demonstrating understanding of the subject |
|under investigation |
[pic]
*ACADEMIC STANDARDS *
|READING, WRITING, SPEAKING & LISTENING |
|1.1.11.A Locate various texts, assigned for independent projects before reading. |
|1.1.11.D Identify strategies that were most effective in learning |
|1.1.11.E Establish a reading vocabulary by using new words |
|1.1.11.F Understanding the meaning of, and apply key vocabulary across the various subject areas |
|1.4.11.D Maintain a written record of activities |
|1.6.11.A Listen to others, ask questions, and take notes |
|MATH |
|2.2.11.A Develop and use computation concepts |
|2.2.11.B Use estimation for problems that don’t need exact answers |
|2.2.11.C Constructing and applying mathematical models |
|2.2.11.D Describe and explain errors that may occur in estimates |
|2.2.11.E Recognize that the degree of precision need in calculating |
|2.3.11.A Selecting and using the right units and tools to measure precise measurements |
|2.5.11.A Using appropriate mathematical concepts for multi-step problems |
|2.5.11.B Use symbols, terminology, mathematical rules, Etc. |
|2.5.11.C Presenting mathematical procedures and results |
|SCIENCE |
|3.1.12.A Apply concepts of systems, subsystems feedback and control to solve complex technological problems |
|3.1.12.B Apply concepts of models as a method predict and understand science and technology |
|3.1.12.C Assess and apply patterns in science and technology |
|3.1.12D Analyze scale as a way of relating concepts and ideas to one another by some measure |
|3.1.12.E Evaluate change in nature, physical systems and man-made systems |
|3.2.12.A Evaluate the nature of scientific and technological knowledge |
|3.2.12.B Evaluate experimental information for appropriateness |
|3.2.12.C Apply elements of scientific inquiry to solve multi – step problems |
|3.2.12.D Analyze the technological design process to solve problems |
|3.4.12.A Apply concepts about the structure and properties of matter |
|3.4.12.B Apply energy sources and conversions and their relationship to heat and temperature |
|3.4.12.C Apply the principles of motion and force |
|3.8.12.A Synthesize the interactions and constraints of science |
|3.8.12.B Use of ingenuity and technological resources to solve specific societal needs and improve the quality of life |
|3.8.12.C Evaluate the consequences and impacts of scientific and technological solutions |
|ECOLOGY STANDARDS |
|4.2.10.A Explain that renewable and non-renewable resources supply energy and material. |
|4.2.10.B Evaluate factors affecting availability of natural resources. |
|4.2.10.C Analyze the use of renewable and non-renewable resources. |
|4.2.12.B Analyze factors affecting the availability of renewable and non-renewable resources. |
|4.3.10.A Describe environmental health issues. |
|4.3.10.B Explain how multiple variables determine the effects of pollution on environmental health, natural processes and human practices. |
|4.3.12.C Analyze the need for a healthy environment. |
|4.8.12.A Explain how technology has influenced the sustainability of natural resources over time. |
|CAREER & EDUCATION |
|13.1.11.A Relate careers to individual interest, abilities, and aptitudes |
|13.2.11.E Demonstrate in the career acquisition process the essential knowledge needed |
|13.3.11.A Evaluate personal attitudes that support career advancement |
|ASSESSMENT ANCHORS |
|M11.A.3.1.1 Simplify expressions using the order of operations |
|M11.A.2.1.3 Use proportional relationships in problem solving settings |
|M11.A.1.2 Apply any number theory concepts to show relationships between real numbers in problem solving |
STUDENT
The student will be able to identify, connect and control the various types of solid state and digital devices used in the electronic field.
TERMINAL PERFORMANCE OBJECTIVE
Given all the electrical tools and materials required, the student will be able to identify, connect and control the various types of solid state and digital devices used in the electronic field.
SAFETY
• Always wear safety glasses when working in the shop.
• Always check with the instructor before turning power on.
• Always use tools in the correct manner.
• Keep work area clean and free of debris.
• Never wire a project without the correct wiring diagram.
• Make sure the tip of the soldering iron/gun is directed towards a safe area.
RELATED INFORMATION
1. Attend lecture by instructor.
2. Obtain handout.
3. Review chapters in textbook.
4. Define vocabulary words.
5. Complete all questions in this packet.
6. Complete all projects in this packet.
7. Complete K-W-L Literacy Assignment by Picking an Article From the
“Electrical Contractor” Magazine Located in the Theory Room. You can pick any article you feel is important to the electrical trade.
EQUIPMENT & SUPPLIES
1. Safety glasses 11. Small bread board
2. Soldering iron/gun 12. 9 Volt battery
3. Screw driver 13. Alligator clips
4. Solder 14. L.E.D. (light Emitting Diode)
5. Wire strippers 15. Small D.C. motor
6. Side cutters 16. Full wave bridge rectifier
7. Cable rippers 17. #22 gauge wire
8. Lineman pliers 18. Power supply
9. Needle nose pliers 19. Solder wick
10. Multimeter 20. In line meter
|VOCABULARY |
|CC.1.3.11-12.I Determine or clarify the meaning of unknown and multiple-meaning words and phrases based on grade level reading and content, |
|choosing flexibly from a range of strategies and tool |
|CC.3.5.11-12.D. Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific |
|or technical context relevant to grades 11–12 texts and topics. |
• Semi-Conductor:
• Electrolytic:
• Diac:
• Junction Diode:
• Resistor:
• Varistor:
• Diode:
• Potentiometer:
• Light Emitting Diode:
• Farad:
• Thermistor:
• Transistor:
• Zener Diode:
• Limit Switch:
• Voltaic Pile:
• Metal Film Resistor:
• S.C.R.
• Hall Effect Device:
• Carbon Film Resistor:
• Hi-Pot:
• Digital Device:
• Limit Switch:
• Fixed resistor:
• Photosensitive Diode:
• Capacitor:
• Voltage Regulator:
• Primary Cell:
• Valence Electrons:
Unit 2
Semiconductors
Objectives
The student will be able to:
Discuss the atomic structure of conductors, insulators, and semiconductors
Discuss how a P-type material is produced
Discuss how an N-type material is produced Conductors
Conductors are materials with lots of free electrons.
The best conductors are metals.
Examples: silver, copper, aluminum
An atom that has only one valence electron makes a great conductor.
Conductors & Insulators
Insulators are materials with very few free electrons.
Atoms with full valence shells make good insulators.
Examples of good insulators:
Rubber, glass, wood, plastic, paper
Semiconductors
Semiconductors are neither good conductors nor good insulators.
Semiconductor materials have four valence electrons in their outer orbit.
Germanium and silicon are the most common semiconductor materials.
A substance with four valence electrons must be mixed with an impurity, such as indium or gallium, to make it a semiconductor.
Process is known as doping
When a semiconductor material has a net positive charge, it is called a P-type material.
When a semiconductor material has a net negative charge, it is called an N-type material.
All solid-state devices are made up of P-type and N-type material.
A diode is the simplest solid-state device. It is made by joining a P-type material with an N-type material to form a PN junction.
Summary
In this unit, we:
Discussed the atomic structure of conductors, insulators, and semiconductors
Examined how P-type and N-type semiconductor materials are produced
Unit 4
The Zener Diode
Objectives
The student will be able to:
Explain the difference between a junction diode and a zener diode.
Discuss common applications of a zener diode.
Connect a zener diode in a circuit.
A Special Diode
A zener diode is designed to be operated with reverse polarity.
It is designed to operate safely in the zener region.
In the zener region, the voltage drop across the zener diode is constant.
Any device connected in parallel with the zener diode will have a constant voltage.
Voltage Drop
In a zener circuit, the supply voltage must be greater than the zener voltage.
The load circuit is connected in parallel with the zener diode.
Thus the voltage across the load is the same as the voltage of the zener diode.
A constant 12 volts will remain across the load.
Voltage Regulator
A zener diode makes a great voltage regulator.
Even if current through the load changes, the voltage across the load will remain constant.
Here is the schematic symbol for a zener diode.
Summary
In this unit, we:
Examined the difference between a junction diode and a zener diode
Discussed the application of a zener diode as a voltage regulator
Saw how the diode is connected in a circuit
Unit 5
The Transistor
Objectives
The student will be able to:
Discuss the difference between PNP and NPN Transistors
Test transistors with an ohmmeter.
Identify the leads of standard, case-style transistors
Discuss the operation of a transistor
Connect a transistor in a circuit
Transistor Construction
Transistors are made with three pieces of semiconductor material.
Common transistors are either NPN or PNP.
An NPN transistor has a positive voltage on its collector and a negative voltage on its emitter. The base is positive.
A PNP transistor has a negative voltage on its collector and a positive voltage on its emitter. The base is negative.
Testing a Transistor with an Ohmmeter
A transistor being tested with an ohmmeter will appear as back-to-back diodes.
If the ohmmeter lead polarity is known, the transistor can be identified as NPN or PNP.
An NPN transistor “looks” to an ohmmeter as though its two diodes have their anodes connected.
A PNP transistor “looks” to an ohmmeter as though its two diodes have their cathodes connected together.
Transistor Operation
A transistor operates as an electric valve.
A large current flows from collector to emitter when a small current flows through the base-emitter.
Thus, with a transistor, a small current controls a much larger current.
Transistor Applications
A transistor can be operated as a digital or an analog device.
As a digital device it is a fast-acting switch. Current either flows or it does not. There are only two states: on or off.
As an analog device, it uses a small voltage to control a much larger one. Current can vary from zero to maximum.
As an analog device, the transistor amplifies a weak incoming signal.
Transistor Case Styles
Transistor case styles are identified with a “TO” marking, meaning “transistor outline.”
Various transistor packages are shown in the figures in the following slide.
Summary
In this unit, we:
Discussed the differences between NPN and PNP transistors
How to test a transistor with an ohmmeter
How to identify transistor lead configurations
Saw how a transistor operates as a digital or analog device
Examined how a transistor is connected in a circuit
Unit 7
The SCR
Objectives
The student will be able to:
Discuss the operation of an SCR in a DC circuit
Discuss the operation of an SCR in an AC circuit
Draw the schematic symbol for an SCR
Discuss phase shifting
Test an SCR with an ohmmeter
Connect an SCR in a circuit
The Multi-Layered SCR
A silicon-controlled rectifier (SCR) is made up of four layers of semiconductor material.
The schematic symbol for an SCR is similar to that for a diode, with the addition of gate lead.
The SCR as a Controlling Device
The SCR is a digital on-off device that is often used to control large amounts of power.
When off, the SCR drops the full supply voltage but conducts no current. Therefore, its power dissipation is zero.
When on, the SCR drops only a volt. Thus, current is limited by the load resistor.
The SCR in a DC Circuit
An SCR can be thought of as a solid-state latching switch.
When the SCR’s anode is positive and its cathode is negative, the SCR is in its “ready” state. It is capable of conducting current.
The SCR in a DC Circuit
When the SCR’s gate receives a positive charge, even for only a short period of time, the SCR will conduct current between its cathode and anode.
Though the SCR has now latched on, its gate has lost control of the SCR.
When the SCR’s current is reduced below the holding current value, the SCR will turn off.
Turning an SCR off is usually accomplished by opening a switch in the cathode or anode circuit.
The SCR in an AC Circuit
The output of an SCR in an AC circuit is direct current.
When the AC waveform drops to zero at the end of each half cycle, the SCR turns off.
The gate must retrigger the SCR for each conduction cycle.
Phase Shifting the SCR
With phase shifting, the SCR can control all of the positive AC waveform.
To phase shift an SCR, the gate circuit must be separated from the anode circuit.
With phase shifting, the SCR is fired as early or as late during the positive half cycle as desired.
Testing the SCR
An SCR can be tested with an ohmmeter.
The positive output lead of the meter is connected to the SCR’s anode.
The negative output lead of the meter is connected to the SCR’s cathode.
If the gate is now touched to the anode of the SCR, the meter will show continuity.
Summary
In this unit, we:
Discussed SCR operation in DC and AC circuits
Examined the SCR schematic symbol
Discussed SCR phase shifting
Saw how to test an SCR with an ohmmeter
Examined an SCR in a circuit
Unit 8
The Diac
Objectives
The student will be able to:
Draw the schematic symbol for a diac
Discuss the operation of a diac
Connect a diac in a circuit
Diac Function
The diac is a special-purpose, bidirectional diode.
Diac operation is similar to that of a UJT.
A diac is a two-directional device.
The diac, unlike a UJT, can operate in an AC circuit.
The diac is used to phase shift a triac.
A Voltage Sensitive Switch
Voltage applied to a diac must reach a predetermined level before it will activate.
When a diac fires, it displays a negative resistance.
A diac will conduct at a lower voltage than the voltage needed to turn it on.
The diac schematic symbol shows back to back diodes.
A Voltage Sensitive Switch
The diac is a voltage sensitive AC switch.
Summary
In this unit, we:
Examined the diac schematic symbol
Discussed diac operation
Saw it connected in an AC circuit
Unit 16
The Solid-State Relay
Objectives
The student will be able to:
Discuss the difference between DC solid-state relays and AC solid-state relays
Discuss opto-isolation
Discuss magnetic isolation
Connect a solid-state relay in a circuit.
Solid-State Relay Basics
The solid-state relay is an all electronic device with no moving parts.
The key advantage of a solid-state relay is that the control input voltage is isolated from the line device the relay is intended to control.
DC and AC Control
Solid-state relays can be used to control both DC and AC loads.
In DC circuits an opto-isolator with a power transistor is often used.
The load side of the relay is optically isolated from the control side of the relay.
With opto-isolation, no voltage spikes or electrical noise produced on the load side of the relay can be transmitted to the control side of the relay.
Solid-state relays used in AC control use a triac instead of a power transistor on the load side.
An LED and photo detector make the “connection” between the control circuit and the load circuit.
Other Control Methods
Some solid-state relays use a small reed-relay to control the output.
A magnetic field built up around the coil causes the reed contacts to attract and close.
Here a magnetic field, rather than a light beam, is used for isolation.
Control Voltages
Control voltages range from 3 to 32 volts.
Control voltages can be DC or AC.
If a triac is used, load voltage ratings of from 120 to 240 volts AC are common.
With a triac, current ratings range from 5 to 25 amps.
Zero Switching
Many solid-state relays have a zero switching feature.
With zero switching, if the relay is “told” to turn off when the AC voltage is in the middle of a cycle, it will continue to conduct until the AC voltage drops to a zero level, and will then turn off.
Packaging
Solid-state relays are available in many different case styles and power ratings.
One of the most common uses of a solid-state relay is in the I/O track of a programmable logic controller.
Summary
In this unit, we:
Discussed the difference between DC and AC solid state relays
Examined opto-isolation
Discussed magnetic isolation
Saw how a solid-state relay is connected in a circuit
Unit 21
Limit Switches
Objectives
The student will be able to:
Explain the use of limit switches in the automatic operation of machines and machine tools
Wire a simple two-wire circuit using a limit switch
Read and draw normally open (NO) and normally closed (NC) wiring symbols
Limit Switch Basics
Limit switches are activated by the motion of machinery or a process.
The limit switch must have high repeat accuracy, be reliable, and have an instantaneous response.
When installing limit switches, one must consider size, operation force, stroke, and manner of mounting.
Limit switches may be used either as control devices for regular operation or as emergency switches to prevent improper functioning of machinery.
Limit switches may be momentary-contact or maintained-contact types.
Micro Limit Switches
Micro limit switches are much smaller than normal limit switches.
With such a switch, only a small amount of travel is required to cause the contacts to close.
Subminiature Micro Switches
These switches operate in a similar manner to the micro switch, yet they are even smaller: approximately one-half to one-fourth the size of the basic switch.
Such switches have contact ratings at from about 1 ampere to 7 amperes.
Summary
In this unit, we:
Examined the use of the limit switch
Studied the schematic symbol for the limit switch.
Unit 25
Hall Effect Sensors
Objectives
The student will be able to:
Describe the Hall effect
Discuss the principles of operation of a Hall generator
Discuss applications in which Hall generators can be used
Principles of Operation
With a Hall Effect generator, a constant current power supply is connected to opposite sides of a piece of semiconductor material.
A sensitive voltmeter is connected to the other two sides.
If current flows straight through the semiconductor, no voltage is developed across the voltmeter.
If a magnetic field is brought near the semiconductor material, the current will be deflected to one side, causing a voltage to appear across the other sides.
Two factors determine the polarity of the voltage produced by the generator:
The direction of current flow through the semiconductor material
The polarity of the magnetic field used to deflect the current
Two factors determine the amount of voltage produced by the generator:
The amount of current flowing through the semiconductor material
The strength of the magnetic field used to deflect the current path
The Hall generator has many advantages:
it is solid-state
it is not affected by dirt, oil, or vibrations
it comes in a convenient integrated circuit package
Motor Speed Sensor
A Hall generator can be used to measure the speed of a rotating device, with a magnet mounted on a disc and a Hall sensor placed nearby.
The frequency of the AC output is proportional to the number of magnetic poles on the disc and the speed of rotation.
Another approach to measuring speed rotation is to use a reluctor, a ferrous metal disk used to shunt a magnetic field away from some other object.
When the notch is between the sensor and the magnet, a voltage is produced.
When the metal is between the sensor and the magnet, a drop in voltage occurs.
Position Sensor
As a position sensor, a Hall generator operates as a digital device that senses the presence or absence of a magnetic field.
In the following figure, we see a Hall generator acting as a limit switch. Such a sensor has no contact wear; it can be used over and over again, millions of times.
Hall Effect Limit Switches
The type of limit switch shown at right uses a Hall generator instead of a set of contacts.
Such switches are operated on DC voltages from 5 to 24 volts.
Current Sensors
If a Hall sensor is mounted near a coil of wire, a voltage will be produced by the generator when current flows through the wire.
The generator can operate at pulse rates as high as 100,000 pulses per second.
Linear Transducers
A linear transducer is designed to produce an output voltage that is proportional to the strength of a magnetic field.
A Hall effect linear transducer can be obtained that has two types of outputs:
A regulated output that produces voltages from 1.5 to 4.5 volts
A ratio metric output that produces an output voltage which is 25% to 75% of the input voltage
Unit 5
Resistors
Objectives:
List the major types of fixed resistors.
Determine the resistance of a resistor using the color code.
Discuss how exceeding its power rating can cause damage to a resistor.
Discuss the use of a variable resistor as a potentiometer.
Resistors are commonly used to perform two functions in a circuit.
The first use is to limit the flow of current in a circuit.
Resistors are commonly used to perform two functions in a circuit.
The second use is to produce a voltage divider.
Fixed resistors have only one ohmic value, which cannot be changed or adjusted. One type of fixed resistor is the composition carbon resistor.
Carbon resistors are very popular for most applications because they are inexpensive and readily available in standard sizes and wattages.
Metal film resistors are another type of fixed resistor. These resistors are superior to carbon resistors because their ohmic value does not change with age and they have improved tolerance.
Wire-wound resistors are fixed resistors that are made by winding a piece of resistive wire around a ceramic core. These are used when a high power rating is required.
The resistor color code can be used to determine the resistor’s ohmic value and tolerance.
Exceeding the power rating causes damage to a resistor.
Variable resistors can change their value over a specific range. A potentiometer is a variable resistor with three terminals. A rheostat has only two terminals.
Schematic symbols are used to represent various types of fixed resistors.
Review:
Resistors are used in two main applications: as voltage dividers and to limit the flow of current in a circuit.
The value of fixed resistors cannot be changed.
There are several types of fixed resistors such as composition carbon, metal film, and wire-wound.
Carbon resistors change their resistance with age or if overheated.
Metal film resistors never change their value, but are more expensive than carbon resistors.
The advantage of wire-wound resistors is their high power ratings.
Resistors often have bands of color to indicate their resistance value and tolerance.
Resistors are produced in standard values. The number of values between 0 and 100 Ω is determined by the tolerance.
Variable resistors can change their value within the limit of their full value.
A potentiometer is a variable resistor used as a voltage divider.
[pic]
UNIT 12
Batteries and Other Sources of Electricity
KEY TERMS
Battery Nickel-cadmium (nicad) cell
Piezoelectricity Cell
Primary cell Current capacity
Secondary cell Electro-motive series of metals
Specific gravity Hydrometer
Thermocouple Internal resistance
Voltaic cell Voltaic pile
Load test
History of the Battery
Briefly go over the history of the battery. Ask students to explain why the saline solution on the frog caused the frog to become a conductor of electricity.
Cells
Explain what a voltaic cell is and describe how easily one can be constructed. If you have the potato, the voltmeter, and the wires needed, hook up this cell for students to see. Explain that the voltage produced is quite small. After describing the cell created in Figure 12-3, ask students if they have ever licked the top of a 9-volt battery to see if it
was still good. Then, ask them if they now understand why they received a slight shock on the tongue (acid or alkali in their saliva acting as an electrolyte).
Cell Voltage
Explain that the type of materials used to make a cell is what determines its voltage. Refer students to the charts of metals in Figure 12-5 and Figure 12-6. Explain the difference between a primary cell and a secondary cell.
Primary Cells
Discuss the process taking place between the zinc and copper suspended in the conductive solution. Have students explain to you what is taking place.
The Carbon-Zinc Cell
Discuss the process Leclanché came up with. Have students explain why this combination of materials worked. Be sure they know what a dry cell battery is.
Alkaline Cells
Describe alkaline cells and compare them to carbon-zinc cells. Discuss the advantages and disadvantages of alkaline cells.
Button Cells
Discuss various types and have students give examples of items that they use button cells in. Explain the differences between mercury-zinc button cells and silver-zinc button cells. Refer students to Figure 12-13 for an excellent view of each part of the mercury button cell.
Lithium Cells
Describe the various types of lithium cells. Discuss why different types of cathode materials can be used, as well as different types of electrolyte substances. Be sure students make note of the shelf life of those using a solid electrolyte. Ask students why that might be important.
Current Capacity and Cell Ratings
Have students write the definition of current capacity into their notes, as well as the statement that the amount of current a particular type of cell can deliver is determined by the surface area of its plates. Hold up a size D cell next to a size AA or AAA cell to illustrate the point.
Discuss the factors necessary to determine a cell’s current capacity. Explain what the milliampere (mA) is, and how it applies to rating primary cells. Go through the process of figuring watt-hours, and watt-hours per cubic inch.
Internal Resistance
Discuss that all cells have internal resistance and how this is affected as the cell is used and ages. Have students explain to you what this means in terms of real milliamperes delivered over a period of time.
12-5 Secondary Cells: Lead-Acid Batteries
Explain what a secondary cell is and ask students for examples. Define specific gravity and explain what a hydrometer is.
Discharge Cycle
Discuss this cycle and have students explain how the hydrometer can be used to check for the level of charge left in the battery.
Charging Cycle
Explain this process and have students give examples of ways this can be done. Also, ask students why they think people are always warned not to smoke around a battery being charged.
Cautions Concerning Charging
In addition to the warning about smoking around a charging battery, be sure students are aware of the other hazards involved with overcharging a battery.
Sealed Lead-Acid Batteries
Describe these types of batteries, referring students to Figure 12-24. Ask students why these types of batteries can be more advantageous than those using a liquid electrolyte.
Ratings for Lead-Acid Batteries
Discuss ampere-hour ratings and how the rating is determined. Also discuss cold cranking amperes for automotive batteries.
Testing Lead-Acid Batteries
Explain the load test and why it might need to be used when the hydrometer reading cannot be trusted. Discuss how the test is conducted and what voltage level should be maintained for the specified amount of time.
12-6 Other Secondary Cells
Nickel-Iron Batteries (Edison Battery)
Describe these cells and discuss their advantages and disadvantages. Discuss in what circumstances they would be more useful than a lead-acid cell.
Nickel-Cadium Batteries
Describe these cells and discuss their advantages and disadvantages. Explain the discharge-recharge memory factor of this cell. Ask students if they have used any cells like this (most camcorder batteries are this type of rechargeable battery with a memory curve).
12-7 Series and Parallel Battery Connections
Explain the effect of connecting batteries or cells in series. Make sure students understand that the voltages add, while the current capacities remain the same. Refer students to Figures 12-28 through 12-30. Emphasize that batteries of different voltages should never be connected in parallel. Go over how batteries can also be connected in a series parallel combination.
12-8 Other Small Sources of Electricity
Solar Cells
Explain what solar cells are and how P-type material and N-type material are formed. Discuss what happens when the photons of light strike the surface of the photo cell. Explain the necessity of creating connections of solar cells in series or parallel or both in order to obtain desired amounts of voltage and current.
UNIT 19
Capacitors
KEY TERMS
Capacitor JAN standard
Dielectric Variable capacitors
Dielectric constant Surface area
Dielectric stress RC time constant
Electrolytic Polarized capacitors
Electrostatic charge Plates
Exponential Non-polarized capacitors
Farad Leakage current
HIPOT
[pic]
19-1 Capacitors
While holding up a capacitor or passing a few around the room, explain what a capacitor is. Be extremely firm when warning students against charging up a capacitor before handing it to someone else. Go over the three things that determine a capacitor’s capacitance, or the electrical size of the capacitor.
Explain what a dielectric is, and review the different types of materials that are used as dielectrics.
Discuss surface area, and how that affects the capacitor and the movement of the electrons from one plate to another.
Be sure students realize that once a capacitor has been charged, it stays charged until a path is introduced for the electrons to travel on. Point out the rule concerning capacitors and current flow.
Explain leakage current and how it occurs. Remind students that insulators are materials with seven or eight valence electrons, and are used because they resist the flow of electricity. Explain that a dielectric is a type of insulator, but that no dielectric is a perfect insulator. The result of this is leakage current, and the possibility of the capacitor becoming a leaky capacitor.
19-2 Electrostatic Charge
Explain how a capacitor stores energy and differentiate between a capacitor’s stored energy and the stored energy of an inductor.
Dielectric Stress
Explain what dielectric stress is and how it occurs. Refer to Figure 19-7 and Figure 19-8 in the text to illustrate.
Describe the potential or stored energy effect that this stress has on the capacitor.
Discuss voltage as it relates to shorting out a capacitor and lowering the life span of a capacitor. Show students how to identify the voltage rating of a capacitor, and warn them, again, of the consequences of exceeding that rating.
Discuss how the energy of the capacitor is stored in the dielectric as an electrostatic charge. Using the examples from the text of the camera .ash and the 0.357 cartridge, ask students if they understand why a charged capacitor should not be handed to someone. Ask about shocks students may have received after sliding across a car seat and touching the car door. Enlarge that for them, exponentially, to communicate the potential waiting to be released from the capacitor.
19-3 Dielectric Constant
Explain how this number is obtained and what it means. Make sure students know that a farad is the basic unit of capacitance.
19-4 Capacitor Ratings
Remind students of what a coulomb is. Explain that the change of a volt across the plates of a capacitor, resulting in the movement of 1 coulomb, gives the capacitor a capacitance of 1 farad.
Go over the chart of various dielectric materials, and the dielectric constant levels of those materials. Remind students that air is always the starting point. Ask students why this is the case, and see if they can relate it back to electrostatic charges.
Carefully go through the steps involved in solving for capacitance of a capacitor. Make sure students understand when to plug in microfarads, nano-farads, and pico-farads to make the problem easier to work with
19-5 Capacitors Connected in Parallel
Discuss connecting capacitors in parallel and why this is done. Go through the simple procedure used to determine the total capacitance of capacitors set up in parallel.
19-6 Capacitors Connected in Series
Distinguish between capacitors set up in series and capacitors set up in parallel. Make sure students understand that a parallel system adds one capacitor to another, for an overall capacitance larger than any one capacitor in the parallel connection. The capacitors in series, however, are the opposite, reducing the overall capacitance when connected in series. Go over the formula used to solve for capacitance when connected in series.
19-7 Capacitive Charge and Discharge Rates
Make sure students understand the difference between changing exponentially versus added change. Two examples you can use are hurricanes and earthquakes. Explain that an earthquake registering a 5 on the Richter scale is not 5/6 as strong as an earthquake registering a level 6. Additionally, a category 3 hurricane is not 3/4 as strong as a category 4 hurricane. Make sure students understand the power potential that accumulates under exponential growth.
Show students, on the board, how the charging pattern occurs in a capacitor at a level of 63.2% of whatever the required charge is, over and over, until the maximum required charge has been reached. Explain that this is also true in reverse for discharging a capacitor.
19-8 RC Time Constants
Explain how to determine the amount of time needed to charge a capacitor that is connected in a circuit with a resistor. Go through the formula and make sure students can use the formula correctly by giving them a couple of practice problems.
19-9 Applications for Capacitors
Provide actual examples or pictures to show students real life applications. Give a general summary of the various everyday uses of capacitors.
19-10 Non-polarized Capacitors
Describe what a non-polarized capacitor is and what it consists of. Discuss its uses and advantages over polarized capacitors.
Explain how oil-filled capacitors are marked, what this indicates, and how students should use this information when connecting the capacitor. Make sure students understand why the way in which the capacitor is connected can either lead to or prevent damage to the item the capacitor is connected to.
19-11 Polarized Capacitors
Distinguish between these capacitors and non-polarized capacitors in their uses and limitations of use. Make sure students realize, however, the difference in capacitance available in a smaller polarized capacitor.
Discuss both the wet and dry types of electrolytic capacitors, and how they are used.
AC Electrolytic Capacitors
Explain the process of shorting out and reforming with this type of wet electrolytic capacitor. Describe when, where, and why this type of capacitor would be needed.
Dry-Type Electrolytic Capacitors
Distinguish it from a wet-type capacitor and describe the gauze makeup of this type of capacitor. Ask students why this internal makeup might be advantageous in a capacitor.
19-12 Variable Capacitors
Compare these capacitors to those with dielectric constants. Explain how the movable plates are used in conjunction with the stationary plates to change the capacitance value.
19-13 Capacitor Markings
Again, show some capacitors and resistors together. It is important for students to feel comfortable distinguishing between the two. Refer back to Figure 5-9 of the text to compare the different color codes of resistors and capacitors.
Discuss the various ways that capacitors are marked, and why these markings vary. Practice on the sample capacitors to see if students can identify the capacitor’s voltage, tolerance, and so on.
Review the EIA standard and the JAN standard with students. Make sure students understand the difference, and know to look for the identifying white dot that indicates the EIA standard being used.
19-14 Temperature Coefficients
Show students where to find this marking on a capacitor. Make sure they know what positive and negative temperature coefficient markings mean.
19-15 Ceramic Capacitors
If you have samples of these, pass them around and compare them to the other samples. Point out the wide color band, indicating the temperature coefficient.
19-16 Dipped Tantalum Capacitors
Provide samples, if possible, to help identify the different shape of this capacitor. Point out how to use the color bands and dots to determine the various values.
19-17 Film Capacitors
Discuss how these capacitors are different, and how their markings are interpreted.
19-18 Testing Capacitors
Discuss the various ways of testing capacitors. Explain how and why some capacitors need to be tested for both capacitance value and the strength of the dielectric.
Review a few testing procedures. Remind students that some capacitors also need to be tested for leakage.
Explain how the dielectric strength test is done and why it is necessary.
Unit Round Up
Review the key terms and go over the summary in class. Have students do the review at home, and then go over it together during your next class. If you have the materials, this would be a great time for the students to gain some hands-on experience. If you do this, warn students, again about the potential energy stored in a capacitor, and why it is not wise (or funny) to give a charged capacitor to anyone.
Be sure to have students fill in the RC time constants chart at the end of the review section. You may want to reproduce this on the board and have students come up, one by one, and show how they solved for the missing values.
REFERENCE PAGES
[pic]
Electronics
Jump to: navigation, search
[pic]
Surface mount electronics
Electronics is the study of the flow of charge through various materials and devices such as semiconductors, resistors, inductors, capacitors, nano-structures and vacuum tubes. Although considered to be a theoretical branch of physics, the design and construction of electronic circuits to solve practical problems is an essential technique in the fields of electronic engineering and computer engineering.
The study of new semiconductor devices and surrounding technology is sometimes considered a branch of physics. This article focuses on engineering aspects of electronics.
Overview of electronic systems and circuits
[pic]
Commercial digital voltmeter checking a prototype.
Electronic systems are used to perform a wide variety of tasks. The main uses of electronic circuits are:
1. The controlling and processing of data.
2. The conversion to/from and distribution of electric power.
Both these applications involve the creation and/or detection of electromagnetic fields and electric currents. While electrical energy had been used for some time prior to the late 19th century to transmit data over telegraph and telephone lines, development in electronics grew exponentially after the advent of radio.
One way of looking at an electronic system is to divide it into 3 parts:
• Inputs – Electronic or mechanical sensors (or transducers). These devices take signals/information from external sources in the physical world (such as antennas or technology networks) and convert those signals/information into current/voltage or digital (high/low) signals within the system.
• Signal processors – These circuits serve to manipulate, interpret and transform inputted signals in order to make them useful for a desired application. Recently, complex signal processing has been accomplished with the use of Digital Signal Processors.
• Outputs – Actuators or other devices (such as transducers) that transform current/voltage signals back into useful physical form (e.g., by accomplishing a physical task such as rotating an electric motor).
For example, a television set contains these 3 parts. The television's input transforms a broadcast signal (received by an antenna or fed in through a cable) into a current/voltage signal that can be used by the device. Signal processing circuits inside the television extract information from this signal that dictates brightness, color and sound level. Output devices then convert this information back into physical form. A cathode ray tube transforms electronic signals into a visible image on the screen. Magnet-driven speakers convert signals into audible sound.
Electronic devices and components
An electronic component is any physical entity in an electronic system whose intention is to affect the electrons or their associated fields in a desired manner consistent with the intended function of the electronic system. Components are generally intended to be in mutual electromechanical contact, usually by being soldered to a printed circuit board (PCB), to create an electronic circuit with a particular function (for example an amplifier, radio receiver, or oscillator). Components may be packaged singly or in more or less complex groups as integrated circuits.
Types of circuits
Analog circuits
[pic]
Hitachi J100 adjustable frequency drive chassis.
Most analog electronic appliances, such as radio receivers, are constructed from combinations of a few types of basic circuits. Analog circuits use a continuous range of voltage as opposed to discrete levels as in digital circuits. The number of different analog circuits so far devised is huge, especially because a 'circuit' can be defined as anything from a single component, to systems containing thousands of components.
Analog circuits are sometimes called linear circuits although many non-linear effects are used in analog circuits such as mixers, modulators, etc. Good examples of analog circuits include vacuum tube and transistor amplifiers, operational amplifiers and oscillators.
Some analog circuitry these days may use digital or even microprocessor techniques to improve upon the basic performance of the circuit. This type of circuit is usually called "mixed signal."
Sometimes it may be difficult to differentiate between analog and digital circuits as they have elements of both linear and non-linear operation. An example is the comparator which takes in a continuous range of voltage but puts out only one of two levels as in a digital circuit. Similarly, an overdriven transistor amplifier can take on the characteristics of a controlled switch having essentially two levels of output.
Digital circuits
Digital circuits are electric circuits based on a number of discrete voltage levels. Digital circuits are the most common physical representation of Boolean algebra and are the basis of all digital computers. To most engineers, the terms "digital circuit", "digital system" and "logic" are interchangeable in the context of digital circuits. In most cases the number of different states of a node is two, represented by two voltage levels labeled "Low"(0) and "High"(1). Often "Low" will be near zero volts and "High" will be at a higher level depending on the supply voltage in use.
Computers, electronic clocks, and programmable logic controllers (used to control industrial processes) are constructed of digital circuits. Digital Signal Processors are another example.
Building-blocks:
Logic gates Schmitt triggers
Adders Multiplexers
Binary Multipliers Registers
Flip-Flops Counters
Highly integrated devices:
Microprocessors Field-programmable gate array (FPGA)
Microcontrollers Digital signal processor (DSP)
Application-specific integrated circuit(ASIC)
Mixed-signal circuits
Mixed-signal circuits refers to integrated circuits (ICs) which have both analog circuits and digital circuits combined on a single semiconductor die or on the same circuit board. Mixed-signal circuits are becoming increasingly common. Mixed circuits are usually used to control an analog device using digital logic, for example the speed of a motor. Analog to digital converters and digital to analog converters are the primary examples. Other examples are transmission gates and buffers.
Heat dissipation and thermal management
Heat generated by electronic circuitry must be dissipated to prevent immediate failure and improve long term reliability. Techniques for heat dissipation can include heat sinks and fans for air cooling, and other forms of computer cooling such as water cooling. These techniques use convection, conduction, & radiation of heat energy.
Noise
Noise is associated with all electronic circuits. Noise is defined [1] as unwanted disturbances superposed on a useful signal that tend to obscure its information content. Noise is not the same as signal distortion caused by a circuit.
Electronics theory
Mathematical methods are integral to the study of electronics. To become proficient in electronics it is also necessary to become proficient in the mathematics of circuit analysis.
Circuit analysis is the study of methods of solving generally linear systems for unknown variables such as the voltage at a certain node or the current though a certain branch of a network. A common analytical tool for this is the SPICE circuit simulator.
Also important to electronics is the study and understanding of electromagnetic field theory.
Electronic test equipment
Electronic test equipment is used to create stimulus signals and capture responses from electronic Devices Under Test (DUTs). In this way, the proper operation of the DUT can be proven or faults in the device can be traced and repaired.
Practical electronics engineering and assembly requires the use of many different kinds of electronic test equipment ranging from the very simple and inexpensive (such as a test light consisting of just a light bulb and a test lead) to extremely complex and sophisticated such as Automatic Test Equipment.
Computer aided design
Today's electronics engineers have the ability to design circuits using pre-manufactured building blocks such as power supplies, semiconductors (such as transistors), and integrated circuits. Electronic design automation software programs include schematic capture programs and printed circuit board design programs. Popular names in the EDA software world are NI Multisim, Cadence (ORCAD), Eagle PCB and Schematic, Mentor (PADS PCB and LOGIC Schematic), Altium (Protel), LabCentre Electronics (Proteus) and many others.
Construction methods
Many different methods of connecting components have been used over the years. For instance, early electronics often used point to point wiring with components attached to wooden breadboards to construct circuits. Cordwood construction and wire wraps were other methods used. Most modern day electronics now use printed circuit boards (made of FR4), and highly integrated circuits. Health and environmental concerns associated with electronics assembly have gained increased attention in recent years, especially for products destined to the European Union, with its Restriction of Hazardous Substances Directive (RoHS) and Waste Electrical and Electronic Equipment Directive (WEEE), which went into force in July 20
Basic Analog Electronic Symbols
|Electronic Symbols |
|[pic] |[pic] |
|Resistors |Capacitors |
|[pic] |[pic] |
|Diodes |Fuses |
|[pic] |[pic] |
|Ground or GND |Inductor or Coil |
|[pic] |[pic] |
|Lamp |Meters |
|[pic] |[pic] |
|Operational Amplifier or Op-Amp |Oscillator Crystal |
|[pic] |[pic] |
|Silicon Controlled Rectifier or SCR |Switch |
|[pic] |[pic] |
|Iron Core Transformer |Bi-Polar Transistors |
ELECTRONIC SYMBOLS CONTINUED
|COMPONENT |SYMBOL |ALTERNATE |
|Ammeter |[pic] | |
|And Gate |[pic] | |
|Antenna, Balanced |[pic] | |
|Antenna, General |[pic] |[pic] |
|Antenna, Loop, Shielded |[pic] | |
|Antenna, Loop, Unshielded |[pic] | |
|Antenna, Unbalanced |[pic] |[pic] |
|Attenuator, Fixed |[pic] | |
|Attenuator, Variable |[pic] | |
|Battery |[pic] | |
|Capacitor, Feedthrough |[pic] | |
|Capacitor, Fixed, Nonpolarized |[pic] | |
|Capacitor, Fixed, Polarized |[pic] | |
|Capacitor, Ganged, Variable |[pic] | |
|Capacitor, General |[pic] | |
|Capacitor, Variable, Single |[pic] | |
|Capacitor, Variable, Split-Stator |[pic] | |
|Cathode, Cold |[pic] | |
|Cathode, Directly Heated |[pic] | |
|Cathode, Indirectly Heated |[pic] |[pic] |
|Cavity Resonator |[pic] | |
|Cell |[pic] | |
|Circuit Breaker |[pic] | |
|Coaxial Cable |[pic] |[pic] |
|Crystal, Piezoelectric |[pic] | |
|Delay Line |[pic] |[pic] |
|Diode, General |[pic] | |
|Diode, Gunn |[pic] | |
|Diode, Light-Emitting |[pic] | |
|Diode, Photosensitive |[pic] | |
|Diode, Photovoltaic |[pic] | |
|Diode, Pin |[pic] | |
|Diode, Varactor |[pic] | |
|Diode, Zener |[pic] | |
|Directional Coupler |[pic] |[pic] |
|Exclusive-Or Gate |[pic] | |
|Female Contact, General |[pic] | |
|Ferrite Bead |[pic] |[pic] |
|Fuse |[pic] |[pic] |
|Galvanometer |[pic] |[pic] |
|Ground, Chassis |[pic] |[pic] |
|Ground, Earth |[pic] | |
|Handset |[pic] | |
|Headphone, Double |[pic] | |
|Headphone, Single |[pic] | |
|Inductor, Air-Core |[pic] | |
|Inductor, Bifilar |[pic] | |
|Inductor, Iron-Core |[pic] | |
|Inductor, Tapped |[pic] | |
|Inductor, Variable |[pic] |[pic] |
|Integrated Circuit |[pic] | |
|Inverter |[pic] | |
|Jack, Coaxial |[pic] | |
|Jack, Phone, 2-Conductor |[pic] | |
|Jack, Phone, 2-Conductor Interrupting |[pic] | |
|Jack, Phone, 3-Conductor |[pic] | |
|Jack, Phono |[pic] | |
|Key, Telegraph |[pic] | |
|Lamp, Incandescent |[pic] | |
|Lamp, Neon |[pic] | |
|Male Contact, General |[pic] | |
|Microphone |[pic] | |
|Nand Gate |[pic] | |
|Negative Voltage Connection |[pic] | |
|Nor Gate |[pic] | |
|Operational Amplifier |[pic] | |
|Or Gate |[pic] | |
|Outlet, Utility, 117-V |[pic] | |
|Outlet, Utility, 234-V |[pic] | |
|Photocell, Tube |[pic] | |
|Plug, Phone, 2-Conductor |[pic] | |
|Plug, Phone, 3-Conductor |[pic] | |
|Plug, Phono |[pic] | |
|Plug, Utility, 117-V |[pic] | |
|Plug, Utility, 234-V |[pic] | |
|Positive Voltage Connection |[pic] | |
|Potentiometer |[pic] |[pic] |
|Probe, Radio-Frequency |[pic] | |
|Rectifier, Semiconductor |[pic] | |
|Rectifier, Silicon-Controlled |[pic] | |
|Rectifier, Tube-Type |[pic] | |
|Relay, DPDT |[pic] | |
|Relay, DPST |[pic] | |
|Relay, SPDT |[pic] | |
|Relay, SPST |[pic] | |
|Resistor |[pic] | |
|Resonator |[pic] | |
|Rheostat |[pic] |[pic] |
|Saturable Reactor |[pic] | |
|Shielding |[pic] | |
|Signal Generator |[pic] | |
|Speaker |[pic] |[pic] |
|Switch, DPDT |[pic] | |
|Switch, DPST |[pic] | |
|Switch, Momentary-Contact |[pic] | |
|Switch, Rotary |[pic] | |
|Switch, SPDT |[pic] | |
|Switch, SPST |[pic] | |
|Terminals, General, Balanced |[pic] | |
|Terminals, General, Unbalanced |[pic] | |
|Test Point |[pic] | |
|Thermocouple |[pic] |[pic] |
|Thyristor |[pic] | |
|Transformer, Air-Core |[pic] | |
|Transformer, Iron-Core |[pic] | |
|Transformer, Tapped Primary |[pic] | |
|Transformer, Tapped Secondary |[pic] | |
|Transistor, Bipolar, npn |[pic] | |
|Transistor, Bipolar, pnp |[pic] | |
|Transistor, Field-Effect, N-Channel |[pic] | |
|Transistor, Field-Effect, P-Channel |[pic] | |
|Transistor, Metal-Oxide, Dual-Gate |[pic] | |
|Transistor, Metal-Oxide, Single-Gate |[pic] | |
|Transistor, Photosensitive |[pic] | |
|Transistor, Unijunction |[pic] | |
|Tube, Diode |[pic] | |
|Tube, Pentode |[pic] | |
|Tube, Photomultiplier |[pic] | |
|Tube, Tetrode |[pic] | |
|Tube, Triode |[pic] | |
|Unspecified Component |[pic] | |
|Voltmeter |[pic] | |
|Wattmeter |[pic] |[pic] |
|Wires |[pic] | |
|Wires, Connected, Crossing |[pic] |[pic] |
|Wires, Not Connected, Crossing |[pic] |[pic] |
Resistor Color Code Chart
Capacitor Operation
[pic]
Inside View of Electrolytic Capacitor
[pic]
Voltaic Pile
[pic]
Mercury Button Cell
[pic]
NAME: LEVEL: DATE:
CHECK LIST FOR SOLID STATE & DIGITAL ELECTRONICS PACKET
STEPS/TASKS MEETS NEEDS
STANDARDS IMPROVEMENT
|1) THE STUDENT COMPLETED ALL VOCABULARY TO 100% ACCURACY. | | |
|2) THE STUDENT COMPLETED ALL WRITTEN WORK TO 100% ACCURACY. | | |
|3) THE STUDENT COMPLETED THE WRITTEN ASSESSMENT TO 80% ACCURACY. | | |
|4) THE STUDENT COMPLETED PERFRMANCE SECTION TO 100% ACCURACY. | | |
* ALL STEPS/TASKS MUST MEET THE STANDARDS IN ORDER TO ACHIEVE MASTERY.*
COMMENTS:
INSTRUCTOR SIGNATURE: DATE:
Projects
Record the color combinations for the following resistors:
(I.E: 300 ohm = Orange, Black, Brown).
• 100 Ohm:
• 2.2 K Ohm:
• 50 Ohm:
• 10 ohm:
• 5K Ohm:
• 10K Ohm:
• 24 Ohm:
• 99 Ohm:
• 75 Ohm:
• 25K Ohm:
• 61,000 Ohm:
Record the minimum and maximum ranges for the following resistors:
(I.E: 25 ohm w/ Silver band = 22.5 Ohms to 27.5 Ohms [Silver = +/- 10%])
• 16 Ohm w/Gold band: to
• 1.5K Ohm w/ no band: to
• 8.8K Ohm: w/ Silver Band: to
• 12 Ohm w/ Gold band: to
• 87K Ohm w/ Silver Band: to
• 100K Ohm w/ Gold Band: to
• 10K Ohm w/ no Band: to
• 50K ohm w/ Gold Band: to
The student will calculate and build a series/parallel circuit.
➢ Student will get the N.O.C.T.I. Kit from cabinet #2.
➢ The student will arrange three resistors’ (100 ohm, 2.2k ohm, and 1k ohm) onto the bread board. The 100 ohm resistor will be in series with the 2.2k ohm and the 1k ohm that are connected in parallel.
➢ The student will solder all connections together using supplied jumpers.
➢ The student will then solder in the connector for the 9 volt battery. [****Polarization is a must when working with D.C. voltage****]
➢ The student will connect the 9 volt power supply to the circuit.
• The student will then record the following readings:
o Total battery voltage:
o Total resistance of circuit:
o Current between R1 (100 ohm) &
R2/R3 2.2k & 1k ohm resistors):
o Total current in circuit:
o Total wattage of circuit:
The student will then calculate the same circuit using the exact readings of the components. You are going to calculate how it comes out using perfect numbers and compare the readings to the ones you recorded. (Perfect Numbers vs. Actual Readings)
o Total battery voltage:
o Total resistance of circuit:
o Current between R1 (100 ohm) &
R2/R3 2.2k & 1k ohm resistors):
o Total current in circuit:
o Total wattage of circuit:
Explain why the exact readings differed from the actual readings (Be specific):
Name: Date:
SOLID STATE AND DIGITAL FUNCTIONS POST TEST
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 1. Solid-state devices are often called
|a. |conductors |c. |semi-insulators |
|b. |semiconductors |d. |insulators |
____ 2. Valence electrons are electrons in the
|a. |inner orbit of an atom |c. |nucleus of an atom |
|b. |outer orbit of an atom |d. |center of an atom |
____ 3. Conductors are generally made from materials that have
|a. |large atoms |c. |charged atoms |
|b. |small atoms |d. |neutral atoms |
____ 4. Insulators are generally made from materials that have
|a. |large atoms |c. |charged atoms |
|b. |small atoms |d. |neutral atoms |
____ 5. Materials that are neither good conductors nor good insulators are known as
|a. |valence conductors |c. |lattice conductors |
|b. |valence insulators |d. |semiconductors |
____ 6. Semiconductors are made from materials that have how many valence electrons in their outer orbits?
|a. |One |c. |Four |
|b. |Two |d. |Eight |
____ 7. Silicon is considered a good
|a. |conductor |c. |insulator |
|b. |semiconductor |d. |none of the above |
____ 8. To make a semiconductor material useful in the production of solid-state components, it is mixed with a (an)
|a. |insulator |c. |another semiconductor |
|b. |conductor |d. |impurity |
____ 9. Electrons
|a. |have a negative charge |c. |are neutral |
|b. |have a positive charge |d. |are made of holes |
____ 10. A material with a positive charge is called a (an)
|a. |N-type material |c. |neutral material |
|b. |P-type material |d. |semiconductor |
____ 11. A material with a negative charge is called a (an)
|a. |N-type material |c. |neutral material |
|b. |P-type material |d. |semiconductor |
____ 12. A device made by joining a piece of P-type material and a piece of N-type material is a
|a. |resistor |c. |diode |
|b. |transistor |d. |triode |
____ 13. The voltage drop across a zener diode
|a. |varies directly with current |
|b. |varies indirectly with current |
|c. |is a function of the load resistor value |
|d. |is constant |
____ 14. In a zener circuit the supply voltage
|a. |must be greater than the zener voltage |
|b. |must be less than the zener voltage |
|c. |must be equal to the zener voltage |
|d. |is a function of load current |
[pic]
____ 15. Referring to the figure above, if the supply voltage is 25 volts, the current through R1 is
|a. |80 mA |c. |130 mA |
|b. |100 mA |d. |200 mA |
____ 16. Referring to the figure above, if R2 was changed to 300 ohms, the maximum current that can flow through the load circuit is
|a. |20 mA |c. |60 mA |
|b. |40 mA |d. |100 mA |
____ 17. The purpose of a zener diode is to
|a. |regulate current |c. |regulate wattage |
|b. |regulate voltage |d. |regulate load resistance |
____ 18. A transistor is made by connecting
|a. |two pieces of semiconductor material |
|b. |three pieces of semiconductor material |
|c. |four pieces of semiconductor material |
|d. |six pieces of semiconductor material |
____ 19. A forward biased NPN transistor must have a
|a. |positive voltage on its collector, a negative voltage on its emitter, and a negative voltage on its base |
|b. |negative voltage on its collector, a positive voltage on its emitter, and a positive voltage on its base |
|c. |negative voltage on its collector, a positive voltage on its emitter, and a negative voltage on its base |
|d. |positive voltage on its collector, a negative voltage on its emitter, and a positive voltage on its base |
____ 20. A forward biased PNP transistor must have a
|a. |positive voltage on its emitter, a negative voltage on its collector, and a negative voltage on its base |
|b. |positive voltage on its emitter, a negative voltage on its collector, and a positive voltage on its base |
|c. |negative voltage on its emitter, a positive voltage on its collector, and a negative voltage on its base |
|d. |negative voltage on its emitter, a positive voltage on its collector, and a positive voltage on its base |
____ 21. In an NPN transistor, the arrow on the emitter points in the direction of
|a. |electron current flow |c. |conventional current flow |
|b. |the higher voltage point |d. |collector voltage |
____ 22. An NPN transistor will appear to an ohmmeter to be
|a. |two diodes with one anode and one cathode connected together |
|b. |two diodes completely isolated from each other |
|c. |two diodes with their cathodes connected |
|d. |two diodes with their anodes connected |
____ 23. In a transistor, the base-emitter current
|a. |is the same as the collector-emitter current |
|b. |is less than the collector-emitter current |
|c. |is greater than the collector-emitter current |
|d. |flows in the opposite direction of the collector-emitter current |
____ 24. If a transistor, operating as a linear device with a gain of 100, has 3 mA of current flowing through its base-emitter junction,
|a. |3 mA flows through its collector-emitter junction |
|b. |300 mA flows through its collector-emitter junction |
|c. |0.03 mA flows through its collector-emitter junction |
|d. |0.3 mA flows through its collector-emitter junction |
____ 25. A transistor can be operated as
|a. |a digital device only |c. |a digital or an analog device |
|b. |an analog device only |d. |neither a digital or an analog device |
____ 26. With a T05 transistor case style, the metal tab on the case is
|a. |closest to the emitter |
|b. |closest to the base |
|c. |closest to the collector |
|d. |of no significants in identifying the emitter, base, or collector leads |
____ 27. With a T03 transistor case style, the case itself is
|a. |the emitter |c. |the collector |
|b. |the base |d. |none of the above |
____ 28. A digital device has
|a. |one state |c. |four states |
|b. |two states |d. |an infinite number of states |
____ 29. An SCR is made up of
|a. |two layers of semiconductor material |
|b. |three layers of semiconductor material |
|c. |four layers of semiconductor material |
|d. |five layers of semiconductor material |
____ 30. An SCR consists of a (an)
|a. |anode, cathode, base |c. |base, emitter, cathode |
|b. |anode, cathode, emitter |d. |cathode, anode, gate |
[pic]
____ 31. Referring to the figure above, if the load resistor was changed to 50 ohms, the SCR would conduct
|a. |1 ampere when turned on |c. |3 amperes when turned on |
|b. |2 amperes when turned on |d. |4 amperes when turned on |
____ 32. When an SCR conducts, the voltage drop across its anode and cathode is approximately
|a. |1 volt |c. |3 volts |
|b. |2 volts |d. |200 volts |
____ 33. If an SCR has a 4 volt drop with 2 amperes of current flowing through it, the SCR is dissipating
|a. |2 watts |c. |6 watts |
|b. |4 watts |d. |8 watts |
____ 34. To turn an SCR on, its
|a. |anode must be positive, its cathode negative, and its gate must receive a positive charge |
|b. |anode must be negative, its cathode positive, and its gate must receive a positive charge |
|c. |anode must be positive, its cathode negative, and its gate must receive a negative charge |
|d. |anode must be negative, its cathode positive, and its gate must receive a negative charge |
____ 35. The amount of current required to keep an SCR turned on is called the
|a. |trigger current |c. |holding current |
|b. |threshold current |d. |break down current |
____ 36. When an SCR fires, current flows through
|a. |the gate to the anode |c. |the anode-cathode section |
|b. |the gate to the cathode |d. |none of the above |
____ 37. When an SCR fires, its
|a. |anode-gate section becomes a short circuit |
|b. |anode-cathode section becomes a short circuit |
|c. |cathode-gate section becomes a short circuit |
|d. |anode-cathode section becomes an open circuit |
____ 38. With a typical SCR, the
|a. |gate current and holding current are equal |
|b. |gate current is greater than the holding current |
|c. |gate current is less than the holding current |
|d. |gate current is at least 20 times greater than the holding current |
____ 39. When an SCR is connected in an ac circuit, the output is
|a. |alternating current |c. |zero current |
|b. |direct current |d. |alternating voltage |
____ 40. To fire an SCR in an ac circuit, it must be
|a. |forward biased while its gate receives a positive charge |
|b. |reverse biased while its gate receives a positive charge |
|c. |forward biased while its gate receives a negative charge |
|d. |reversed biased while its gate receives a negative charge |
____ 41. Referring to the figure below, the voltage across the load can be adjusted from
[pic]
|a. |0 to half the applied voltage |
|b. |0 to the full applied voltage |
|c. |half the applied voltage to the full applied voltage |
|d. |0 to one-fourth the applied voltage |
____ 42. The diac is a special-purpose
|a. |unidirectional diode |c. |bidirectional transistor |
|b. |bidirectional diode |d. |bidirectional SCR |
____ 43. The primary function of a diac is to phase shift
|a. |a UJT |c. |an SCR |
|b. |a diode |d. |a triac |
____ 44. A diac is similar to a (an)
|a. |common transistor |c. |triac |
|b. |SCR |d. |UJT |
____ 45. When a diac fires, it displays a
|a. |positive resistance |c. |zero resistance |
|b. |negative resistance |d. |infinite resistance |
____ 46. A diac conducts at
|a. |a lower voltage than that needed to turn it on |
|b. |a higher voltage than that needed to turn it on |
|c. |the same voltage needed to turn it on |
|d. |twice the voltage needed to turn it on |
____ 47. A diac conducts
|a. |on only one side of an ac cycle |c. |in a dc circuit only |
|b. |on either side of an ac cycle |d. |in a 60 Hz ac circuit only |
____ 48. A diac is a
|a. |current sensitive dc switch |c. |voltage sensitive dc switch |
|b. |current sensitive ac switch |d. |voltage sensitive ac switch |
____ 49. A triac operates as a back to back
|a. |diode |c. |diac |
|b. |unijunction transistor |d. |silicon-controlled rectifier |
____ 50. When a triac is connected in a circuit, the output voltage results in a (an)
|a. |pulsating direct current |c. |alternating current |
|b. |pulsating alternating current |d. |direct current |
____ 51. A triac operates in a manner similar to two
|a. |SCRs with a common anode |c. |SCRs with a common gate |
|b. |SCRs with a common cathode |d. |UJTs with a common base |
____ 52. A triac requires
|a. |a holding current but no gate current |
|b. |a gate current but no holding current |
|c. |both a holding current and a gate current |
|d. |neither a holding current or a gate current |
____ 53. A triac has
|a. |one state of operation |c. |three states of operation |
|b. |two states of operation |d. |four states of operation |
____ 54. When a triac is turned on, it drops
|a. |zero volts with circuit current limited by the gate resistance |
|b. |zero volts with circuit current limited by the load resistance |
|c. |about 1 volt with circuit current limited by the gate resistance |
|d. |about 1 volt with circuit current limited by the load resistance |
____ 55. A triac works well in industrial circuits as a (an)
|a. |dc switch |c. |pulsating switch |
|b. |ac switch |d. |holding switch |
____ 56. If a triac is fired when the ac waveform reaches its peak value,
|a. |half the ac voltage is dropped across the triac and half across the load |
|b. |none of the ac voltage is dropped across the triac and all the voltage is dropped across the load |
|c. |all the ac voltage is dropped across the triac and none is dropped across the load |
|d. |none of the ac voltage is dropped across the triac and none across the load |
[pic]
____ 57. Referring to the figure above, a
|a. |resistor is used to phase shift the triac |
|b. |diode is used to phase shift the triac |
|c. |diac is used to phase shift the triac |
|d. |capacitor is used to phase shift the triac |
____ 58. Referring to the figure above, when the triac turns on,
|a. |capacitor C1 charges through the gate of the triac |
|b. |capacitor C1 discharges through the gate of the triac |
|c. |capacitor C1 charges through the MT1 terminal of the triac |
|d. |capacitor C1 discharges through the MT1 terminal of the triac |
____ 59. Which is not true of a solid-state relay?
|a. |It has no moving parts |
|b. |It is sealed against dirt |
|c. |It is resistant to shock and vibration |
|d. |It requires a relatively high operating voltage |
____ 60. With an opto-isolator, coupling from the control circuit to the load circuit is accomplished with
|a. |heat |c. |electrical pulses |
|b. |light |d. |electromagnetism |
____ 61. Solid-state relays designed for use as ac controllers use a (an)
|a. |diac in the load circuit |c. |power transistor in the load circuit |
|b. |triac in the load circuit |d. |SCR in the load circuit |
____ 62. With a reed switch, coupling from the control circuit to the load circuit is accomplished with
|a. |heat |c. |electrical pulses |
|b. |light |d. |electromagnetism |
____ 63. Zero switching is used primarily with
|a. |resistive loads |c. |inductive loads |
|b. |capacitive loads |d. |pulsed loads |
____ 64. Which is not an important factor in the installation of limit switches?
|a. |Operating force |c. |Size |
|b. |Stroke |d. |Power distribution |
____ 65. The best material for use in a Hall generator is
|a. |gold |c. |a semiconductor |
|b. |silver |d. |an insulator |
____ 66. In a Hall effect, a
|a. |constant current flows through a semiconductor material |
|b. |constant voltage is placed across a semiconductor material |
|c. |constant current flows through a conducting material |
|d. |constant voltage is placed across a conducting material |
____ 67. With a Hall generator, an external
|a. |electrical field is brought near the Hall sensor |
|b. |heating element is brought near the Hall sensor |
|c. |magnetic field is brought near the Hall sensor |
|d. |none of the above |
____ 68. The amount of voltage produced by a Hall generator is determined by
|a. |the amount of current flowing through its semiconductor material |
|b. |the strength of the magnetic field used to deflect the current path |
|c. |a and b |
|d. |neither a or b |
____ 69. A Hall generator is constructed as a (an)
|a. |coiled device |c. |capacitive device |
|b. |vacuum device |d. |integrated circuit |
____ 70. If a disk with magnetic poles around its circumference is attached to a rotating shaft, and a Hall sensor is mounted near the disk, a (an)
|a. |steady dc voltage will be produced |
|b. |pulsating dc voltage will be produced |
|c. |ac voltage will be produced |
|d. |all of the above |
____ 71. A sensor used to shunt a magnetic field away from some other object is known as a
|a. |detector |c. |pulser |
|b. |reactor |d. |reluctor |
____ 72. A reluctor circuit will produce a (an)
|a. |dc voltage |c. |ac voltage |
|b. |pulsating dc voltage |d. |zero voltage |
____ 73. A Hall generator can be used in a manner similar to a
|a. |limit switch |c. |hydraulic switch |
|b. |pressure switch |d. |all of the above |
____ 74. A Hall effect limit switch uses
|a. |a magnetic plunger |c. |normally open contacts |
|b. |rotating contacts |d. |normally closed contacts |
____ 75. A Hall generator can operate at pulse rates as high as
|a. |1000 pulses per second |c. |100,000 pulses per second |
|b. |10,000 pulses per second |d. |1,000,000 pulses per second |
Residential & Industrial Electricity
K-W-L WORKSHEET
NAME: LEVEL: DATE:
ARTICLE TITLE:
TIME START: TIME FINISH:
| | |
|K What do I already KNOW | |
|about this topic? | |
| | |
|W What do I WANT to know | |
|about this topic? | |
| | |
|L What did I LEARN after | |
|reading ABOUT this | |
|topic? | |
I checked the following before reading:
➢ Headlines and Subheadings
➢ Italic, Bold, and Underlined words
➢ Pictures, Tables, and Graphs
➢ Questions or other key information
I made predictions AFTER previewing the article.
Comments:
• Instructor Signature:
• Instructional Aide Signature:
Name: Date:
SOLID STATE AND DIGITAL FUNCTIONS PRE TEST
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 1. Solid-state devices are often called
|a. |conductors |c. |semi-insulators |
|b. |semiconductors |d. |insulators |
____ 2. Valence electrons are electrons in the
|a. |inner orbit of an atom |c. |nucleus of an atom |
|b. |outer orbit of an atom |d. |center of an atom |
____ 3. Conductors are generally made from materials that have
|a. |large atoms |c. |charged atoms |
|b. |small atoms |d. |neutral atoms |
____ 4. Insulators are generally made from materials that have
|a. |large atoms |c. |charged atoms |
|b. |small atoms |d. |neutral atoms |
____ 5. Materials that are neither good conductors nor good insulators are known as
|a. |valence conductors |c. |lattice conductors |
|b. |valence insulators |d. |semiconductors |
____ 6. Semiconductors are made from materials that have how many valence electrons in their outer orbits?
|a. |One |c. |Four |
|b. |Two |d. |Eight |
____ 7. Silicon is considered a good
|a. |conductor |c. |insulator |
|b. |semiconductor |d. |none of the above |
____ 8. To make a semiconductor material useful in the production of solid-state components, it is mixed with a (an)
|a. |insulator |c. |another semiconductor |
|b. |conductor |d. |impurity |
____ 9. Electrons
|a. |have a negative charge |c. |are neutral |
|b. |have a positive charge |d. |are made of holes |
____ 10. A material with a positive charge is called a (an)
|a. |N-type material |c. |neutral material |
|b. |P-type material |d. |semiconductor |
____ 11. A material with a negative charge is called a (an)
|a. |N-type material |c. |neutral material |
|b. |P-type material |d. |semiconductor |
____ 12. A device made by joining a piece of P-type material and a piece of N-type material is a
|a. |resistor |c. |diode |
|b. |transistor |d. |triode |
____ 13. The voltage drop across a zener diode
|a. |varies directly with current |
|b. |varies indirectly with current |
|c. |is a function of the load resistor value |
|d. |is constant |
____ 14. In a zener circuit the supply voltage
|a. |must be greater than the zener voltage |
|b. |must be less than the zener voltage |
|c. |must be equal to the zener voltage |
|d. |is a function of load current |
[pic]
____ 15. Referring to the figure above, if the supply voltage is 25 volts, the current through R1 is
|a. |80 mA |c. |130 mA |
|b. |100 mA |d. |200 mA |
____ 16. Referring to the figure above, if R2 was changed to 300 ohms, the maximum current that can flow through the load circuit is
|a. |20 mA |c. |60 mA |
|b. |40 mA |d. |100 mA |
____ 17. The purpose of a zener diode is to
|a. |regulate current |c. |regulate wattage |
|b. |regulate voltage |d. |regulate load resistance |
____ 18. A transistor is made by connecting
|a. |two pieces of semiconductor material |
|b. |three pieces of semiconductor material |
|c. |four pieces of semiconductor material |
|d. |six pieces of semiconductor material |
____ 19. A forward biased NPN transistor must have a
|a. |positive voltage on its collector, a negative voltage on its emitter, and a negative voltage on its base |
|b. |negative voltage on its collector, a positive voltage on its emitter, and a positive voltage on its base |
|c. |negative voltage on its collector, a positive voltage on its emitter, and a negative voltage on its base |
|d. |positive voltage on its collector, a negative voltage on its emitter, and a positive voltage on its base |
____ 20. A forward biased PNP transistor must have a
|a. |positive voltage on its emitter, a negative voltage on its collector, and a negative voltage on its base |
|b. |positive voltage on its emitter, a negative voltage on its collector, and a positive voltage on its base |
|c. |negative voltage on its emitter, a positive voltage on its collector, and a negative voltage on its base |
|d. |negative voltage on its emitter, a positive voltage on its collector, and a positive voltage on its base |
____ 21. In an NPN transistor, the arrow on the emitter points in the direction of
|a. |electron current flow |c. |conventional current flow |
|b. |the higher voltage point |d. |collector voltage |
____ 22. An NPN transistor will appear to an ohmmeter to be
|a. |two diodes with one anode and one cathode connected together |
|b. |two diodes completely isolated from each other |
|c. |two diodes with their cathodes connected |
|d. |two diodes with their anodes connected |
____ 23. In a transistor, the base-emitter current
|a. |is the same as the collector-emitter current |
|b. |is less than the collector-emitter current |
|c. |is greater than the collector-emitter current |
|d. |flows in the opposite direction of the collector-emitter current |
____ 24. If a transistor, operating as a linear device with a gain of 100, has 3 mA of current flowing through its base-emitter junction,
|a. |3 mA flows through its collector-emitter junction |
|b. |300 mA flows through its collector-emitter junction |
|c. |0.03 mA flows through its collector-emitter junction |
|d. |0.3 mA flows through its collector-emitter junction |
____ 25. A transistor can be operated as
|a. |a digital device only |c. |a digital or an analog device |
|b. |an analog device only |d. |neither a digital or an analog device |
____ 26. With a T05 transistor case style, the metal tab on the case is
|a. |closest to the emitter |
|b. |closest to the base |
|c. |closest to the collector |
|d. |of no significants in identifying the emitter, base, or collector leads |
____ 27. With a T03 transistor case style, the case itself is
|a. |the emitter |c. |the collector |
|b. |the base |d. |none of the above |
____ 28. A digital device has
|a. |one state |c. |four states |
|b. |two states |d. |an infinite number of states |
____ 29. An SCR is made up of
|a. |two layers of semiconductor material |
|b. |three layers of semiconductor material |
|c. |four layers of semiconductor material |
|d. |five layers of semiconductor material |
____ 30. An SCR consists of a (an)
|a. |anode, cathode, base |c. |base, emitter, cathode |
|b. |anode, cathode, emitter |d. |cathode, anode, gate |
[pic]
____ 31. Referring to the figure above, if the load resistor was changed to 50 ohms, the SCR would conduct
|a. |1 ampere when turned on |c. |3 amperes when turned on |
|b. |2 amperes when turned on |d. |4 amperes when turned on |
____ 32. When an SCR conducts, the voltage drop across its anode and cathode is approximately
|a. |1 volt |c. |3 volts |
|b. |2 volts |d. |200 volts |
____ 33. If an SCR has a 4 volt drop with 2 amperes of current flowing through it, the SCR is dissipating
|a. |2 watts |c. |6 watts |
|b. |4 watts |d. |8 watts |
____ 34. To turn an SCR on, its
|a. |anode must be positive, its cathode negative, and its gate must receive a positive charge |
|b. |anode must be negative, its cathode positive, and its gate must receive a positive charge |
|c. |anode must be positive, its cathode negative, and its gate must receive a negative charge |
|d. |anode must be negative, its cathode positive, and its gate must receive a negative charge |
____ 35. The amount of current required to keep an SCR turned on is called the
|a. |trigger current |c. |holding current |
|b. |threshold current |d. |break down current |
____ 36. When an SCR fires, current flows through
|a. |the gate to the anode |c. |the anode-cathode section |
|b. |the gate to the cathode |d. |none of the above |
____ 37. When an SCR fires, its
|a. |anode-gate section becomes a short circuit |
|b. |anode-cathode section becomes a short circuit |
|c. |cathode-gate section becomes a short circuit |
|d. |anode-cathode section becomes an open circuit |
____ 38. With a typical SCR, the
|a. |gate current and holding current are equal |
|b. |gate current is greater than the holding current |
|c. |gate current is less than the holding current |
|d. |gate current is at least 20 times greater than the holding current |
____ 39. When an SCR is connected in an ac circuit, the output is
|a. |alternating current |c. |zero current |
|b. |direct current |d. |alternating voltage |
____ 40. To fire an SCR in an ac circuit, it must be
|a. |forward biased while its gate receives a positive charge |
|b. |reverse biased while its gate receives a positive charge |
|c. |forward biased while its gate receives a negative charge |
|d. |reversed biased while its gate receives a negative charge |
____ 41. Referring to the figure below, the voltage across the load can be adjusted from
[pic]
|a. |0 to half the applied voltage |
|b. |0 to the full applied voltage |
|c. |half the applied voltage to the full applied voltage |
|d. |0 to one-fourth the applied voltage |
____ 42. The diac is a special-purpose
|a. |unidirectional diode |c. |bidirectional transistor |
|b. |bidirectional diode |d. |bidirectional SCR |
____ 43. The primary function of a diac is to phase shift
|a. |a UJT |c. |an SCR |
|b. |a diode |d. |a triac |
____ 44. A diac is similar to a (an)
|a. |common transistor |c. |triac |
|b. |SCR |d. |UJT |
____ 45. When a diac fires, it displays a
|a. |positive resistance |c. |zero resistance |
|b. |negative resistance |d. |infinite resistance |
____ 46. A diac conducts at
|a. |a lower voltage than that needed to turn it on |
|b. |a higher voltage than that needed to turn it on |
|c. |the same voltage needed to turn it on |
|d. |twice the voltage needed to turn it on |
____ 47. A diac conducts
|a. |on only one side of an ac cycle |c. |in a dc circuit only |
|b. |on either side of an ac cycle |d. |in a 60 Hz ac circuit only |
____ 48. A diac is a
|a. |current sensitive dc switch |c. |voltage sensitive dc switch |
|b. |current sensitive ac switch |d. |voltage sensitive ac switch |
____ 49. A triac operates as a back to back
|a. |diode |c. |diac |
|b. |unijunction transistor |d. |silicon-controlled rectifier |
____ 50. When a triac is connected in a circuit, the output voltage results in a (an)
|a. |pulsating direct current |c. |alternating current |
|b. |pulsating alternating current |d. |direct current |
____ 51. A triac operates in a manner similar to two
|a. |SCRs with a common anode |c. |SCRs with a common gate |
|b. |SCRs with a common cathode |d. |UJTs with a common base |
____ 52. A triac requires
|a. |a holding current but no gate current |
|b. |a gate current but no holding current |
|c. |both a holding current and a gate current |
|d. |neither a holding current or a gate current |
____ 53. A triac has
|a. |one state of operation |c. |three states of operation |
|b. |two states of operation |d. |four states of operation |
____ 54. When a triac is turned on, it drops
|a. |zero volts with circuit current limited by the gate resistance |
|b. |zero volts with circuit current limited by the load resistance |
|c. |about 1 volt with circuit current limited by the gate resistance |
|d. |about 1 volt with circuit current limited by the load resistance |
____ 55. A triac works well in industrial circuits as a (an)
|a. |dc switch |c. |pulsating switch |
|b. |ac switch |d. |holding switch |
____ 56. If a triac is fired when the ac waveform reaches its peak value,
|a. |half the ac voltage is dropped across the triac and half across the load |
|b. |none of the ac voltage is dropped across the triac and all the voltage is dropped across the load |
|c. |all the ac voltage is dropped across the triac and none is dropped across the load |
|d. |none of the ac voltage is dropped across the triac and none across the load |
[pic]
____ 57. Referring to the figure above, a
|a. |resistor is used to phase shift the triac |
|b. |diode is used to phase shift the triac |
|c. |diac is used to phase shift the triac |
|d. |capacitor is used to phase shift the triac |
____ 58. Referring to the figure above, when the triac turns on,
|a. |capacitor C1 charges through the gate of the triac |
|b. |capacitor C1 discharges through the gate of the triac |
|c. |capacitor C1 charges through the MT1 terminal of the triac |
|d. |capacitor C1 discharges through the MT1 terminal of the triac |
____ 59. Which is not true of a solid-state relay?
|a. |It has no moving parts |
|b. |It is sealed against dirt |
|c. |It is resistant to shock and vibration |
|d. |It requires a relatively high operating voltage |
____ 60. With an opto-isolator, coupling from the control circuit to the load circuit is accomplished with
|a. |heat |c. |electrical pulses |
|b. |light |d. |electromagnetism |
____ 61. Solid-state relays designed for use as ac controllers use a (an)
|a. |diac in the load circuit |c. |power transistor in the load circuit |
|b. |triac in the load circuit |d. |SCR in the load circuit |
____ 62. With a reed switch, coupling from the control circuit to the load circuit is accomplished with
|a. |heat |c. |electrical pulses |
|b. |light |d. |electromagnetism |
____ 63. Zero switching is used primarily with
|a. |resistive loads |c. |inductive loads |
|b. |capacitive loads |d. |pulsed loads |
____ 64. Which is not an important factor in the installation of limit switches?
|a. |Operating force |c. |Size |
|b. |Stroke |d. |Power distribution |
____ 65. The best material for use in a Hall generator is
|a. |gold |c. |a semiconductor |
|b. |silver |d. |an insulator |
____ 66. In a Hall effect, a
|a. |constant current flows through a semiconductor material |
|b. |constant voltage is placed across a semiconductor material |
|c. |constant current flows through a conducting material |
|d. |constant voltage is placed across a conducting material |
____ 67. With a Hall generator, an external
|a. |electrical field is brought near the Hall sensor |
|b. |heating element is brought near the Hall sensor |
|c. |magnetic field is brought near the Hall sensor |
|d. |none of the above |
____ 68. The amount of voltage produced by a Hall generator is determined by
|a. |the amount of current flowing through its semiconductor material |
|b. |the strength of the magnetic field used to deflect the current path |
|c. |a and b |
|d. |neither a or b |
____ 69. A Hall generator is constructed as a (an)
|a. |coiled device |c. |capacitive device |
|b. |vacuum device |d. |integrated circuit |
____ 70. If a disk with magnetic poles around its circumference is attached to a rotating shaft, and a Hall sensor is mounted near the disk, a (an)
|a. |steady dc voltage will be produced |
|b. |pulsating dc voltage will be produced |
|c. |ac voltage will be produced |
|d. |all of the above |
____ 71. A sensor used to shunt a magnetic field away from some other object is known as a
|a. |detector |c. |pulser |
|b. |reactor |d. |reluctor |
____ 72. A reluctor circuit will produce a (an)
|a. |dc voltage |c. |ac voltage |
|b. |pulsating dc voltage |d. |zero voltage |
____ 73. A Hall generator can be used in a manner similar to a
|a. |limit switch |c. |hydraulic switch |
|b. |pressure switch |d. |all of the above |
____ 74. A Hall effect limit switch uses
|a. |a magnetic plunger |c. |normally open contacts |
|b. |rotating contacts |d. |normally closed contacts |
____ 75. A Hall generator can operate at pulse rates as high as
|a. |1000 pulses per second |c. |100,000 pulses per second |
|b. |10,000 pulses per second |d. |1,000,000 pulses per second |
-----------------------
NAME:'(5IKU??‘•?ž¢¤¨«®¯ÐÑÒÚA N V W \ ] ^ _ d ® òäÜØÑÍÉÅØ»·Ø·°Ñ«·Ø •Š ØÅ؆†{†ØÑwØjc
hk6Ðh,l{h¥x`h,l{5?B*phÿÿÿh’A;h\.
h,l{5?>*[pic]h,l{
* |h¦]hM¼5?>*[pic]
* |h¦]h§|`5?>*[pic]
* |h¦]hA,Ë5?>*[pic] hA,Ë5?
h70"5?>*[pic]h70"h70"h70"5?>*[pic]hM¼hšauhºS—
hA,Ë5?>*[pic]hA,ËjhA,ËU[pic]jhM9ñU[pic]mHnHu[pic]jh¦]U[pic]mH
DATE:
DATE DUE:
RESIDENTIAL & INDUSTRIAL ELECTRICITY
[pic]
Level 3
Schuylkill Technology Center-
South Campus
15 Maple Avenue
Marlin, Pennsylvania 17951
(570) 544-4748
*CORE CURRICULUM STANDARDS*
*ACADEMIC STANDARDS*
................
................
In order to avoid copyright disputes, this page is only a partial summary.
To fulfill the demand for quickly locating and searching documents.
It is intelligent file search solution for home and business.
Related searches
- xfinity homepage for windows 10
- make xfinity my homepage in windows 10
- change homepage to xfinity for windows 10
- set edge homepage to xfinity
- set xfinity as homepage windows 10
- change homepage to xfinity by comcast
- comcast homepage email sign in
- beaumont isd homepage teams
- xfinity homepage download
- ask homepage free download
- ask homepage download
- change homepage to ask