Hands-On-Physics Introductory Electronics Unit Messing Around: ACTIVITY #3

1. Use the circuit board to wire two small light bulbs in series, as shown in the circuit diagram. You will have to solder leads onto the bulbs.
   
2. If you add a third bulb to the circuit, what do you think will happen to the brightness of the bulbs? Try it and see.
   
   
3. Think about the charge leaving the battery and circulating through each bulb. Why does adding a third bulb change things?
   
   
4. Use your multimeter to measure the current and voltage at various points. Record these readings on your circuit diagram.
   
   
5. Wire two bulbs in parallel, as shown in the circuit diagram.
   
6. Think about the charges from the battery going through the two loops. Compare the brightness of these bulbs to the bulbs in series. What will happen when you add a third bulb?
   
   
7. Again use the multimeter to measure the current and voltage at various points and record them on your circuit diagram.
   
   
8. Wire a combination circuit, shown in the circuit diagram below. Note the relative brightness of the bulbs. Predict what will happen to the remaining bulbs when you remove any one of them. Verify your predictions.
   
9. Again use the multimeter to measure the current and voltage at various points and record them on your circuit diagram.

Reporting

1. Why are bulbs brighter in a parallel circuit than a series circuit? Use the words 'voltage' and 'current' in your answer.
   
   
2. Which will drain a battery faster, a series or parallel circuit? Explain your answer.
   
   
3. Examine a Mystery Board, prepared by your teacher. Predict the circuit underneath by unplugging bulbs and using your multimeter. Go back to the circuit you built in #8 and change it so it duplicates the one built by your teacher. Draw a circuit diagram for the Mystery Board.