Science experiment on measuring current and voltage in different parts of the circuit.

1. CURRENT & VOLTAGE IN A
CIRCUIT
YEAR 9 – ELECTRICITY
By S. Choi

2. AIM & HYPOTHESIS
• Aim: To measure the
current and voltage at
different parts of an
electric circuit.
• Hypothesis: Write your
own hypothesis on your
experimental report.

3. EQUIPMENT
• 1 × DC power pack
• 1 × light globe
• 1 × switch
• 1 × ammeter
• 1 × voltmeter
• 6 × connecting wires

4. RISK ASSESSMENT
Risk
Injury
Prevention

5. METHOD
1. Set up the circuit as
shown in the diagram on
the RHS.
2. With the switch OPEN,
use the ammeter to
measure the electric
current at points: B, C &
D. Record the results in
the results table.
3. With the switch
CLOSED, repeat step 2.
Record the results in the
results table.

6. METHOD
4. With the switch OPEN, use
the voltmeter to measure the
voltage across:
- Points E & A (power pack)
- Points A & B (connecting wire)
- Points B & C (switch)
- Points C & D (light globe)
- Points D & E (connecting wire)
Record the results in the
results table.
5. With the switch CLOSED,
repeat step 4. Record the
results in the results table.

7. RESULTS
Current in different parts of the circuit
Switch
Circuit location
B
OPEN
C
D
B
CLOSED
C
D
Current (A)

8. RESULTS
Voltage in different parts of the circuit
Switch
Circuit location
Across E & A (power pack)
Across A & B (connecting wire)
OPEN
Across B & C (switch)
Across C & D (light globe)
Across D & E (connecting wire)
Across E & A (power pack)
Across A & B (connecting wire)
CLOSED
Across B & C (switch)
Across C & D (light globe)
Across D & E (connecting lead)
Voltage (V)

9. DISCUSSION
1. Was the current at points B, C & D the same or
different when the switch was CLOSED?
2. Was the current at points B, C & D the same or
different when the switch was OPEN?
3. Across which parts of the circuit were there readings in
the voltmeter when the switch was CLOSED?
4. Across which parts of the circuit were there readings in
the voltmeter when the switch was OPEN?
5. Explain how voltmeter readings occur even though the
switch is not closed.
6. Compare the voltage across the terminals of the power
pack with the voltage across the light globe.

10. CONCLUSION
• Write your own conclusion of the experiment.