Series Resistance, Explained

Resistors wired end-to-end form a single path for current. Because the same current must push through each one, their resistances add directly: Rt = R1 + R2 + R3 + …. Series is the complement of parallel: where parallel divides, series accumulates.

Voltage Drops Add Up

Each series resistor drops a voltage proportional to its resistance — VR = I × R — and Kirchhoff's voltage law guarantees the drops sum to the supply. This voltage-splitting behavior is exactly what makes series networks the basis of voltage dividers and LED current limiters.

One Path, One Weakness

The single-path nature of series circuits is both their strength and their weakness: current is identical everywhere, which simplifies analysis, but a single open component stops the whole circuit. Household wiring uses parallel for exactly this reason — so one blown fuse doesn't darken the house.