Steven Philley
Converters Circuits Codes LED R V div I div S∥P RC RL X LC Cap L Filter RL F Turns Site contents

Vol. IV — Electronics · Tool

Capacitor codes

Ceramics often wear a three-digit EIA mark instead of a printed µF. Decode the digits to pF / nF / µF, or type a value and snap to a nearby E12 code.

First two digits are the value; the third is the power-of-ten multiplier in pF. Optional letter = tolerance.

How it works

A three-digit EIA code is picofarads written like a resistor: 104 means 10 × 10⁴ pF = 100 000 pF = 100 nF = 0.1 µF. Codes that end in 0 keep the first two digits as the literal picofarad value (220 → 22 pF).

A trailing letter is tolerance: J ±5%, K ±10%, M ±20%, Z +80/−20%, and a few absolute-pF letters for tiny ceramics. Lookup snaps to the E12 series (10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82) before encoding.

Pair this with Resistor codes for the ohm twin, RC time once you know C, or the converters bench for everyday ohms and watts.