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Series and parallel resistor calculator

Total resistance of resistors in series or in parallel.

Try the circuit in the labBuild it on the simulator's bench and measure it.

How it is worked out

In series the same current flows through every resistor, so the resistances add: R = R1 + R2 + …. In parallel every resistor has the same voltage, so the currents add and 1/R = 1/R1 + 1/R2 + …. The parallel total is always smaller than the smallest resistor.

Two equal resistors in parallel give half the value: two 1 kΩ make 500 Ω, and each carries half the current and half the heat, a common way to make a resistor that handles more power.

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