Series Parallel Resistor Calculator

Frequently Asked Questions

• How do series resistors add?

  In series (end-to-end), total resistance = R1 + R2 + R3... Example: 10Ω + 20Ω + 30Ω = 60Ω. Series increases total resistance. Current is same through all; voltage divides.

• How do parallel resistors add?

  In parallel (same nodes), 1/Rtotal = 1/R1 + 1/R2 + 1/R3... Example: 10Ω || 20Ω || 30Ω = 5.45Ω. Parallel decreases resistance. Voltage is same across all; current divides.

• What is series-parallel combination?

  Mixed circuit with some resistors in series, others in parallel. Solve by breaking into sub-networks, find each equivalent, then combine. Work from innermost (most complex) outward.

• Why are parallel resistors lower than series?

  Parallel provides multiple current paths, reducing total opposition. Series is single path, adding opposition.

• What is current division in parallel?

  Current splits inverse to resistance: I1/I2 = R2/R1. Lower resistance gets more current.

• What is voltage division in series?

  Voltage divides proportional to resistance: V1 = Vin × R1/(R1+R2). Higher resistance gets more voltage.

• How do I analyze mixed series-parallel?

  Identify series segments (add), parallel segments (reciprocal add), then combine. Always work from components outward to total resistance.

• What is equivalent resistance?

  Single resistor value that would draw same current as the network. Used to simplify circuit analysis.