Practice with Circuit building



Series and Parallel Circuit Lab

Basic Circuit – 1 light bulb:

1) You are making a doll house for your little sister or brother and you want to put a light in the living room. You go to Radio Shack and the salesman gives you a light bulb, some wires, a switch, and a battery. Show how you think these would need to be connected.

2) Now test your diagram by creating it in the PhET simulation.

➢ PhET simulation website

➢ Electricity, Magnets & Circuits

➢ Construction Kit (DC only)

a. Revise your drawing, if you need to.

b. Pay special attention to where the wires connect to the light bulb. In the diagram you drew, do you think the current would be forced to go through the light bulb’s filament, or could it bypass it?

c. If it could bypass it, make changes to your diagram to force the current to go through the filament.

3) What do you need to do to force the current to go through the lightbulb?

The “brightness” of 1 light bulb:

4) What do you think you could do to make the dollhouse light bulb shine brighter? Make a list, and then compare with those at your table.

5) Now try it using the simulation. What things worked? What didn’t?

6) What do you think you could do to make the light bulb dimmer? Make a list, and then compare with those at your table.

7) Now try it using the simulation. What things worked? What didn’t?

Adding more light bulbs:

■ Suppose you wanted to light up 3 lights at once (for track lighting in the dollhouse)

Build each circuit shown below using the circuit board in the simulation. After you’ve made each one, determine what the schematic would look like (change the radio button from “lifelike” to “schematic”.) Then draw it. The bulbs will not change to the schematic symbol in the simulation, use the symbol from your class notes.

8) 3 light bulbs in series

9) 3 light bulbs in parallel

Measuring Voltage and Current

1. Make a series circuit with 3 lights and 1 battery (remember series and circle)

2. Add a voltmeter over the light.

3. Add a non-contact ammeter.

4. Take readings for each light.

5. Repeat with parallel.

|Series |Parallel |

|[pic] |[pic] |

Data:

| |Source |Amperage at |Amperage going |

| |Voltage |source |into bulb 1 |

| | |voltage | |

|1 | | | |

|2 | | | |

|3 | | | |

Figure 1 Figure 2 Figure 3

18) Summarize the relationships you observed and explain what you think is happening.

19) Test to see if changing the battery voltage causes you to modify any of your conclusions. Explain what you measured and any conclusions you draw from your tests

20) What happens when you take a wire out of a circuit? Explain what you think is happening

21) Practice using the voltmeter and realistic ammeter in several circuits. Describe how using a voltmeter is different from using an ammeter.

Using voltage in parallel circuits

Redo Part III but use figures 4-6 for the circuits.

|# of bulbs |Battery |Current into|Brightness of |

| |voltage (v) |battery (A) |bulbs |

|1 | | | |

|2 | | | |

|3 | | | |

Figure 4 Figure 5 Figure 6

22) Summarize the relationships you observed and explain what you think is happening.

23) Test to see if changing the battery voltage causes you to modify any of your conclusions. Explain what you measured and any conclusions you draw from your tests

Switches

24) Switches allow the flow of electrons to be stopped. Practice putting a switch into your last circuit that turns off

a. All bulbs (Draw the schematic of this circuit.)

b. One bulb (Draw the schematic of this circuit.)

c. Two bulbs (Draw the schematic of this circuit.)

Conductors and Insulators

Create a series circuit with one bulb in CCK using the items found in the Grab Bag.

25) Which items allow the current to flow?

26) Which items do not allow currents to flow?

Short Circuits

A short circuit is an alternate path that does not go through a load. Build the following circuits and add in an extra wire as shown by the dashed line. Close the switch and answer the questions.

27) What happens when there is a short circuit in a series circuit?

28) What happens to the flow of the electrons?

29) What happens when there is a short circuit in a parallel circuit?

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10) Light bulbs in both series & parallel: Which of the light bulbs do you think will be the brightest? Why?

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