Ceramic Disc Capacitor Values / Code / Label

Ceramic disc capacitor codes usually consist of three numbers followed by a letter, and they are very easy to decode to determine the value. The example capacitor shown, the first two significant digits represent the first two digits of the actual value, which is 47. The third digit is the multiplier, which is ×1000. The letter J signifies the tolerance of ±5 %. Since this is the EIA coding system, the value will be in picofarads. Hence the value of the capacitor above is 47000 pF ±5 %.

A ceramic disc capacitor does not have a polarity and connects in any direction on the printed circuit board. If you are new to capacitor codes, then the best way to start is with a chart, because that way, you can see the arrangement of the code. Engineers usually do not require calculators because the code is so simple. Here is another example, code 104 is 10 followed by four zeros, hence 10,0000 pF. As you can see, it is so easy that you can do this in your head.

How to read Capacitor Codes

EXAMPLES: If a capacitor is marked 103J, its value is 10000 pF ±5 %. If a capacitor is marked 335K, its value is 3300000 pF ±10 %

Standard Capacitor Values

Here is a list of the currently available ceramic disc capacitors consisting of standard values. Large electronics suppliers will tend to stock all of these.

Voltage Code

The brown coloured ones usually have an underline below the marking, which means 50 V / 100 V. If there is no underline, then the rating is 500 V, assuming the manufacturer follows the marking scheme.

The epoxy-coated capacitors usually have the letters 1KV, which indicates 1000 V, and 2KV indicating 2000 V.

Sometimes capacitors do not have any markings regarding voltage rating and you have to look up the documentation of that component. However, most manufacturers often use a combination of the above marking scheme.

Temperature Code

The black mark at the top of the disc represents the operating temperature range, which is approximately -25 °C to +85 °C.

Replacement

Ceramic disc capacitors come in many versions, and for basic general applications, the brown ceramic disc types are usually used for decoupling in low voltage circuits.

For switched-mode power supply applications, epoxy coated flame retardant capacitors are usually used. These meet the UL 94-V0 standard. They were originally used in the line-output stages of conventional CRT based television sets.

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