Two Resistors in Series

Also known as series resistance

R_{t} = R_{1} + R_{2}

R_t =

R_1 =

R_2 =

Enter your known values, leave one input blank, and solves for the missing one. Try different units for next level excitement!

Learning zone

Resistors wired end to end carry the same current, so each adds its own voltage drop and their opposition simply stacks: total resistance is the sum. Old-style Christmas-light strings worked this way — dozens of small resistances in one chain, which is also why one burned-out bulb darkened the whole string.

Two Resistors in Series

R_{t} = R_{1} + R_{2}

Where

$R_{t}$ = Total resistance
$R_{1}$ = Resistance 1
$R_{2}$ = Resistance 2

Missing one of these? Work it out first, then come back

Total resistance — Ohm's Law, Electrical Power (P = I²R)
Resistance 1 — Ohm's Law, Electrical Power (P = I²R)
Resistance 2 — Ohm's Law, Electrical Power (P = I²R)

Part of this formula set

Series and parallel networks

4 formulasCombining resistors and capacitors two at a time — and the reason the two components follow exactly opposite rules.