Current Lab
Purpose:
You will measure and compare current at different points in a circuit.
You will compare current in circuits with one or two bulbs.
**To measure current, the meter must be place IN the circuit so current has to flow through the meter. THIS MEANS THE CIRCUIT MUST BE OPEN.**
Materials:
Multimeter with leads, battery, wires, bulbs, bulb holders
Procedure: Part 1
You will measure and compare current at different points in a circuit.
You will compare current in circuits with one or two bulbs.
**To measure current, the meter must be place IN the circuit so current has to flow through the meter. THIS MEANS THE CIRCUIT MUST BE OPEN.**
Materials:
Multimeter with leads, battery, wires, bulbs, bulb holders
Procedure: Part 1
- Build a test circuit like Circuit 1 to the right, with a battery and bulb. Find the two metal connections on each side of the bulb. Observe in the diagram where point A and point B are. (You will need to identify these parts as we continue.)
- Connect the meter leads to the meter in order to read current (red lead goes into the 10A port; black lead goes into the COM port). Dial needs to be pointed at A. See above to help you measure the current.
- Disconnect the positive terminal of the battery and the bulb holder.
- Place the red lead of the meter on the positive terminal of the battery and the black lead on the bulb holder, completing the circuit.
- Record the current reading in a table.
- Following the same procedure you did for point A on your circuit, use your meter to measure the current at point B. The positive lead of the meter should be closest to the negative battery terminal.
- Record the current reading in a table.
- Remove the meter and reconnect the circuit. Record your observation of the brightness of your bulb. Leave it connected in preparation for part 2.
Procedure: Part 2
- Add a second bulb and bulb holder to your circuit from part 1.
- You should have a circuit that mirrors the diagram on the right. Make sure you can identify points A, B & C on your circuit.
- Record your observation about the brightness of the bulbs compared to part 1.
- Using the same procedure from part 1, measure and record the current at point A.
- Measure and record the current at point B.
- Measure and record the current at point C.
Analysis: (Create a text response on Edmodo to answer these three questions!)
- Look at your two current readings for Circuit 1. What conclusions can you draw from this information?
- Review all three current readings for Circuit 2. What conclusions can you draw from this information?
- What happened when you added a bulb to the circuit? Cite your data to support your claim.