Friday, August 15, 2014

Capacitor color coding; Capacitor coding; How to find capacitor value

Most of the capacitor values has been written on them especially on electrolytic capacitors, like 10μF that stands for 10 micro-Farads. For them, the value is straight-forward. There are some smaller types of capacitors with a coded 2 or 3 digits number on them. If there are 2 digits printed on them, then this is the exact value in pico-farads. For example, 21 means 21 Pico-Farads. For the 3 digits code, the first 2 digits are the significant digits (in pico-Farads) and the third is the multiplier. The multiplier digit is as follows:

Multiplier
digit
Multiplier
value
0
1
1
10
2
100
3
1.000
4
10.000
5
100.000
6
7
8
0,01
9
0,1

A capacitor with code 322 means 32*100 pico-Farads = 3200 pF=3,2 nano-Farads.
Sometimes, a tolerance letter is also added at the end of the code. These letter tolerances are as follows:

Tolerance
letter
Tolerance
value
D
+/- 0.5
F
+/- 1%
G
+/- 2%
H
+/- 3%
J
+/- 5%
K
+/- 10%
M
+/- 20%
P
+100% ,-0%
Z
+80%, -20%


So a 103J is a 10,000 pF with +/-5% tolerance
Capacitance is measured in “farads.” There are picofarads (pF),nanofarads (nF), and microfarads (μF).
Color coded capacitors always have 4 bands, and are measured in picofarads – the smallest unit of measurement.
Equivalents: 1,000,000pF (picofarads) = 1,000nF (nanofarads) = 1μF (microfarad)


Capacitors color code

Things may get a little more complicated in this section so make sure that reading a value from a carbon resistor is clear for you.This color code is mostly applied to ceramic capacitors, but could be also met to other types of capacitors too. It is not very popular, but is good to know how it works. And here is how it goes:
Same as a resistor, a capacitor's color code is read in even way. Notice that on the left side as you see the cap there mast be an thicker strip or the strip must be at the edge of the capacitor. If you have a disc type capacitor then there is no problem of course. The first strip is the temperature coefficient. You can ignore this strip. The second and the third strip are the significant digits and the fourth strip is the multiplier (result in pico Farads). Use the same methodology as reading a resistor to get the value of the capacitor. For example:


Lets choose a capacitor having color coding as below:-
Second strip:
 Orange (3)
Third strip:
 Red (2)
Fourth strip (Multiplier):
 Orange (x 1.000)

This capacitor's value should be 32*1000=32.000 pF=32nF
 


The tolerance is different for capacitors less than 10pF and for capacitors more than 10pF. For the previous example, the capacitor is more than 10pF. If the last strip was green, the tolerance should be +/-0.5%.
Above given table for capacitors is self explanatory.