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Capacitors
Electrolytic capacitors have value printed on its body. Pins can be easily identified. Large pin is positive. Moreover a black
band is printed near the negative terminal to identify the polarity. Do not change the polarity. Capacitor will explode. In Disc
capacitors, only a number is printed on its body so it is very difficult to determine its value in PF, KPF, uF, n etc. In some
capacitor, its value is printed in uF eg.0.1 in some others EIA code is used e.g. 104. The following tricks can solve the problem.
1. One or two numbers on the capacitor represents value in PF e.g. 8 = 8PF
2. If the third number is zero, then the value is in P e.g. 100 = 100PF
3. If the capacitor has three numbers and the third number is not a zero, it represents the number of zeros after the first
and second digits e.g. 104 = 10 – 0000 PF
4. If the value is obtained in PF, it is easy to convert it into KPF or uF
PF / 1000 = KPF or n
PF / 10, 00000 = uF
For example, if the capacitor is 104, then it is 10-0000 PF or 100 KPF or n or 0.1 uF
5. Conversion formula
n x 1000 = PF
PF/1000 = n
PF/1,000,000 = uF
n=1/1,000,000,000F uF = 1/ 1000,000 F
uF x 1,000,000 = PF
uF x 1,000,000/1000 = n
6. English letter below the value represents tolerance e.g. 473 = 473 K
K
If the capacitor has four digits and the fourth digit is a zero, then the value is in PF. E.g. 1500 = 1500PF
7. If a number is represented with a decimal, the value is in uF. E.g. 0.1 = 0.1 uF
8. If an alphabet is given below the digits, it represents a decimal and the value is in KPF or n
E.g. 2K2 = 2.2 KPF
9. If the values are given with slashes, the first digit represents value in UF, second its tolerance and third
its maximum voltage rating E.g. 0.1/5/800 = 0.01 uF / 5 % / 800 Volt.
Some common disc capacitors are
EIA Code
PF
KPF/N
UF
102
103
104
202
203
223
224
1
10
100
2
20
-
1
10
100
2
20
22
220
0.001
0.01
0.1
0.002
0.02
0.022
0.22
EIA
Code
403
471
472
473
442
443
444
KPF/N
UF
40
0.47
4.7
47
4.4
44
440
0.4
0.00047
0.0047
0.047
0.0044
0.044
0.44
Polyester capacitors have five colour bands similar to the resistor colour code value.
Band 1
Band 2,3,4
Band 5
Temperature tolerance
Value in PF as per colour code used in resistors
Tolerance
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