Capacitor code calculator
Type what is printed on a capacitor to read its value, tolerance and rated voltage. Film and ceramic capacitors print a three-figure code; electrolytics print the value and the voltage in full.
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47 nF, 100 V
47 nF capacitor, 5%, 100 V
47 followed by the multiplier 3, in picofarads: 47 nF. Printed this way on film and larger ceramic capacitors; small chip ceramics are usually not printed at all. 2A is the rated-voltage code for 100 V. J is the tolerance, ±5%.
The three-figure code
Two figures and a multiplier, in picofarads: 104 is 10 followed by four zeros, 100,000 pF, which is 100 nF or 0.1 µF. 473 is 47 nF, and 220 is 22 pF.
Under 10 pF the third figure is 9 for × 0.1 and 8 for × 0.01, so 479 is 4.7 pF. The same three figures on a chip resistor are ohms: 104 there is 100 kΩ, and only the body tells the two apart.
The tolerance letter
A letter after the code is its tolerance, as IEC 60062 lists the letters: 104J is 100 nF ±5%.
| Letter | Tolerance |
|---|---|
| F | ±1%, or ±1 pF on a capacitor under 10 pF |
| G | ±2%, or ±2 pF on a capacitor under 10 pF |
| J | ±5% |
| K | ±10% |
| M | ±20% |
| Z | −20% to +80% |
| B | ±0.1 pF, on a capacitor under 10 pF |
| C | ±0.25 pF, on a capacitor under 10 pF |
| D | ±0.5 pF, on a capacitor under 10 pF |
The voltage code
A rated-voltage code can stand in front of the value: 2A473J is 100 V, 47 nF, ±5%. The figure is the decade and the letter the value.
| Code | Voltage | Code | Voltage |
|---|---|---|---|
| 0E | 2.5 V | 0G | 4 V |
| 0L | 5.5 V | 0J | 6.3 V |
| 1A | 10 V | 1C | 16 V |
| 1D | 20 V | 1E | 25 V |
| 1V | 35 V | 1H | 50 V |
| 1J | 63 V | 1K | 80 V |
| 2A | 100 V | 2Q | 110 V |
| 2B | 125 V | 2C | 160 V |
| 2Z | 180 V | 2D | 200 V |
| 2P | 220 V | 2E | 250 V |
| 2F | 315 V | 2V | 350 V |
| 2G | 400 V | W6 | 420 V |
| 2W | 450 V | 2H | 500 V |
| 2L | 550 V | 2J | 630 V |
The codes as the type numbering system of Nichicon's aluminium electrolytic capacitor catalogue CAT.8100K lists them. Deki Electronics numbers its polyester film capacitors with codes of the same form, and gives five of them other voltages: 1K is 70 V, 2F 300 V, 2L 800 V, 2P 1200 V and 2Q 575 V. On those, the datasheet settles it.
Electrolytic capacitors
Electrolytics print the value and the voltage in full: 47µF 25V, sometimes 47µ 25V, or with the µ as the decimal point, 4µ7 for 4.7 µF.
They are polarised: on an aluminium can the stripe marks the negative lead. One that has dried out can still read close to its value on a capacitance range while its ESR has risen, which only an ESR meter shows. A domed or leaking top means it has failed.
Tantalum capacitors
A moulded tantalum prints the code and a voltage letter: 106C is 10 µF at 16 V, and makers print the letter before or after the figures. Its band marks the positive end, the opposite of an aluminium electrolytic.
Inductors, fuses and resistors
Inductors use the same figures in microhenries: 101 is 100 µH and 4R7 is 4.7 µH. A glass fuse prints its rating to IEC 60127: T2AL250V is a 2 A time-lag fuse with a low breaking capacity, rated 250 V. The search reads both. Through-hole resistors carry the colour code.