Resistors in series or parallel

Series resistances add directly. In parallel, conductances add, so the equivalent resistance is always smaller than the smallest branch resistance.

Formula usedR_series = ΣR · 1/R_parallel = Σ(1/R)

Calculate

Choose the connection, then enter resistor values separated by commas.

Two worked examples

Example 1

100 Ω, 220 Ω and 330 Ω in series give 650 Ω.

Example 2

100 Ω and 100 Ω in parallel give 50 Ω.

Good to knowEnter any number of resistor values separated by commas or spaces.