Thursday, June 2, 2016

How to calculate the value of a ceramic capacitor

You might have come across situations were you needed to calculate the value of a ceramic capacitor. Today a large variety of such capacitors are available in the market but the value calculation of all remains the same. All these capacitors are marked with a three digit number code, say, 104. There are two key points to remember in the value calculation. First point is that in the marked number code the first two digits are the significant digits and the third digit is the multiplier. The second point is that the final value is in the 'pico Farad' unit (without conversion).

For example, a value 104 on the capacitor indicates that the value of the capacitor is 10 x 104 pF or 100 nano Farads (μF) or 0.1 micro Farads (μF). Some other codes and their corresponding values are given below:

Capacitor
Code
Value in pF
Value in μF
101
100
0.0001
102
1000
0.001
103
10000
0.01
104
100000
0.1
105
1000000
1


For some capacitors there will be an additional alphabet code at the end of the number marking say 104J. This alphabet code indicates the capacitor tolerance. The tolerance values are calculated as given in the table below

Code Tolerance
C ±0.25pF
J ±5%
K ±10%
M ±20%
D ±0.5pF
Z +80% / -20%

For example, 104J coded capacitor has the value 0.1 ± 5% μF. 
For a 104C coded capacitor, the value is 0.1 μF ± 0.25pF

No comments:

Post a Comment