High Power Amp Teaching Resources
www.kitronik.co.uk/2143
Ceramic Disc Capacitors
Values
The value of a capacitor is measured in Farads, though a 1 Farad capacitor
would be very big. Therefore we tend to use milli Farads (mF), micro Farads
(
F), nano Farads (nF) and pico Farads (pF). A
F is a millionth of a Farad, 1
F
= 1000 nF and 1nF = 1000 pF.
The larger electrolytic capacitors tend to have the value printed on the side of
them along with a black band showing the negative lead of the capacitor.
Other capacitors, such as the ceramic disc capacitor shown on the right, use a
code. They are often smaller and may not have enough space to print the
value in full, hence the use of the 3-digit code. The first 2 digits are the first
part of the number and the third digit gives the number of zeros to give its
value in pF.
Example:
104 = 10 + 0000 (4 zero’s) =
100,000 pF
(which is also 0.1
F)
Work out what value the four capacitors are in the table below.
Printing on capacitor
Two digit start
Number of zero’s
Value in pF
222
103
333
473
1F
= 1,000mF
1F
= 1,000,000
F
1F
= 1,000,000,000nF
1F
= 1,000,000,000,000pF
