Activity B: Resistance
Measurement of Resistance
Resistance of a Resistor can be determined by simultaneously measuring potential drop across it and current flowing through it. To do this we will create circuit depicted opposite. A switch is included in circuit to minimize use of Battery.
Throughout this experiment 3 Resistors will be used. Their values are 3 Ω, 5.6 Ω, 10 Ω.
(1) Plug ends of Red and Black 24" cables into Red and Black Current Sensor's connectors respectively.
(2) Make connections on Electronics Board between Battery, Switch and 3 Ω Resistor using Orange and Grey wires as shown.
(3) Connect Voltage Sensor's Red and Black plugs at each end of Resistor as shown.
(4) Plug in Current Sensor's Red and Black cables as shown.
Circuit is now complete.
(5) Depress Switch, keep it depressed. Click Start. After 1 s click Stop, release Switch.
Potential drop across Resistor and current flowing though it will appear below.
Potential Drop (V) across Resistor
Current (A) flowing through Resistor
Resistor (Ω)
Potential (V)
Current (A)
3
5.6
10
(6) Record values oppposite.
(7) Repeat (2) to (6) for 5.6 Ω Resistor.
(8) Repeat (2) to (6) for 10 Ω Resistor.
(9) Use measured potential and current values and equation V = I·R to determine actual resistances of Resistors.
Measured Resistances (Ω)
3
5.6
10
For accuracy reasons, we will use measured resistance values rather than nominal ones in the calculations in this experiment.
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