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Physics · Electricity · Class Demonstration
Ohm's Law Laboratory
Build the circuit, flip the switch, and watch the ammeter & voltmeter needles respond in real time.
1 Circuit Diagram
How it works: the dry cell drives current through the rheostat and resistor R. The ammeter (in series) reads the current I; the voltmeter (in parallel with R) reads the potential difference V across it.
2 Enter Any Two Values
volts
amperes
ohms (Ω)
Switch
Ammeter
0.00 A
Voltmeter
0.00 V
1 Circuit Diagram
Key idea: in series, the same current I flows through R1 and R2, but the supply voltage divides — V1 = I·R1 and V2 = I·R2, with V1 + V2 = V.
2 Supply & Resistors
Switch
Ammeter (I — same everywhere)
0.00 A
Voltmeter
0.00 V
1 Circuit Diagram
Key idea: in parallel, R1 and R2 share the same voltage V, but the current divides — I1 = V/R1 and I2 = V/R2, with the main ammeter reading I1 + I2.
2 Supply & Resistors
Switch
Ammeter
0.00 A
Voltmeter (V — same on both branches)
0.00 V
