How to read Capacitor Codes

Grab an LCR or Capacitance meter, read the value of the capacitor you wish to replace. This is assuming the capacitor you are replacing is not damaged beyond the point of a reasonably accurate reading.

Larger capacitors, like electrolytic, have the value printed on them clearly, such as 10uF, but smaller types often have just 2 or three numbers on them.

2 Numbers: These are read as Pico-Farads. An example: 47 printed on a small disk can be assumed to be 47 Pico-Farads (or 47pF).

3 Numbers: The first two are the 1^st and 2^nd significant digits and the third is a multiplier code. Most of the time the last digit tells you how many zeros to write after the first two digits, but this is not ALWAYS the case. eg. an extra digit might be indicating an ESR value.

Capacitor Speak - milli, micro, nano, pico,

1 milli Farad (or any other unit) is 1/1,000th  or .001 times the unit. (10^-3)

1 micro = 1/1,000,000 or 0.000 001 times the unit (10^-6 )

1 nano = 1/1,000,000,000 or 0.000 000 001 times the unit (10^-9 )

1 pico = 1/1,000,000,000,000 or 0.000 000 000 001 times the unit (10^-12 )

Example: A capacitor marked 104 is 10 with 4 more zeros or 100,000pF which is otherwise referred to as a 0.1uF capacitor.

Tolerance code is given by a single letter. Example a 103J is a 10,000 pF with +/-5% tolerance

Exceptions: There is sometimes a letter-number-letter (like Z5U) code that gives additional information.
Example. A 224 Z5U would be a 220,000 pF (or .22 uF) cap with a low temperature rating of -10 deg C a high temperature rating of +85 Deg C and a tolerance of +22%,-56%.

There are some Capacitor colour codes - the last dot is the tolerance code where brown is +/-1% red +/-2% as in the resistor colour code with two exceptions black is +/- 20% and white is +/- 10% going backward the three dots to the left of the tolerance dot form the value in pF There will be two or three more colour dots before the value but they mean different things about temperature range and coefficient depend which one of three systems is used.

There are two more number systems seen on caps. The first one can be recognized as the EIA because it starts with an R.

R DM 15 F 471(R) J 5 O (C)

The above number means the following

This next one is a Military code example:

CM 15 B D 332 K N 3

 

Table 4 characteristic codes
EIA or MIL characteristic code	Maximum capacitance drift	Maximum range of Temp coefficient
B	Not specified	Not specified
C	+/-(0.5% + 0.1pF)	+/- 200 ppm/°C
D	+/-(0.3% + 0.1pF)	+/- 100 ppm/°C
E	+/-(0.1% + 0.1pF)	-20 to +100 ppm/°C
F	+/-(0.05% + 0.1pF)	0 to +70 ppm/°C

 

Table 5 Temperature range
M	-55 to 70 °C
N	-55 to 85 °C
O	-55 to 125 °C
P	-55 to 150 °C

 

Table 6 Mil voltage range code in volts
A	100
B	250
C	300
D	500
E	600
F	1,000
G	1,200
H	1,500
J	2,000
K	2,500
L	3,000
M	4,000
N	5,000
P	6,000
Q	8,000
R	10,000
S	12,000
T	15,000
U	20,000
V	25,000
W	30,000
X	35,000

Cog or NPO refer to caps that don't have any temperature drift (at least in theory.)

CONVERSION TABLE - uF - nF - pF

To use this table, just read across. For example, 1uF is same 1,000nF or 1,000,000pF.