Code 104 = 100 nFEpoxy dip coatingBent pins · 5 mm spacing

Orange or blue flat disc, “104” code on top, two legs
Disc diameter ≈ 4–10 mm, lead spacing 2.5 or 5 mm

Capacitors

Ceramic disc

In simple terms

What is this?

A small, non-polarised bucket of electricity; it holds little but fills and empties very quickly.

What is it for?

Placed next to the IC, it absorbs noise; the circuit works stably.

Where do you see it?

Small discs on radios, toys and every kind of board.

How do you spot it?

A flat round disc and two legs; a three-digit code such as 104 is printed on it.

Caution:

No polarity to worry about, but don't get the code reading wrong; 104 means one hundred nanofarads.

Technical definition

A small non-polarized capacitor made of a thin ceramic disc with metal coating on both faces. Its value is written as a three-digit code: 104, 10 and four zeros, in pF, which is 100 nF. It is cheap and the most-used capacitor on a breadboard.

Code104 = 100 nF

Voltage50 V

PolarityNone

Schematic symbol Same in IEC and ANSI

IEC 60617: the drawing style used in Türkiye and Europe.

Pins 2

1Pin 1Has no direction, fits either way1

2Pin 2Has no direction, fits either way2

Features typical

Capacitance range: 1 pF – 100 nF
Voltage: 50 V typical (kV types also exist)
Reading the code: 104 = 100 nF · 103 = 10 nF · 22 = 22 pF
Tolerance: ±10% (K) · ±20% (M) · +80/−20% (Z)
Dielectric: Class 1 (NP0/C0G) · Class 2
Example part: 104 (100 nF, 50 V)

Common mistakes

Not reading the code as pF104 is not 104 pF: it is 10 and four zeros, so 100 000 pF = 100 nF.

Placing it far from the chipPlace the decoupling capacitor as close as possible to the chip’s supply pin; a long connection reduces its effect.

Test with a multimeter

Test whether this part is good with the multimeter on the measurement screen.

Take a measurement

Where it is used

Decoupling the chip supplySuppressing motor noiseSimple RC filter10 nF on the CTRL pin of 555