Reading Values Printed on Electrolytic Capacitors is Easy, Digits on Ceramic Capacitors Need to Know Some Theory. Like resistors has some coding which needs to decipher, printed digits on ceramic capacitors also needs deciphering. Here is How to Read Ceramic Capacitor Values. Values are normally printed on capacitors in Micro Farad (uF) with voltage. 10^6 (10 to the power 6) Pico Farad (pf) is equal to 1 Micro Farad (uF).
We can not directly measure capacitance with ordinary multimeters like that we have shown on article on multimeter for dummies. The multimeters which can read capacitance are usually costlier, better.
How to Read Ceramic Capacitor Values?
Ceramic capacitors usually uses 3 digits like 102, 103, 101 for indicating their values and the values are in term of Pico farad. The numbering system is easy to use, if you remember it is based on picofarads, not microfarads.
If a ceramic capacitor has three digits – ABC, then the value would be AB*10^C Pico Farad. If ABC is 104 then the digit 104 means 10*104pF = 100000pF = 100nF = 0.1uF. The first two digits of printed code are the first two digits of capacitor value and the third digit gives the number of zeroes to be added so as to get capacitor value in Pico Farad.
If we calculate in Nano Farad for values ending with 4, then the reading becomes easy like 104 is 100 nF.
If we calculate in Nano Farad for values ending with 3, then the reading becomes easy like 103 is 10 nF.
Rarely some of the ceramic capacitors are polarized, have positive and negative terminals. In addition to the capacitance value, the capacitor may be marked by its tolerance. There are several tolerance marking systems used two of the most common with one and two alphabets. Unless you are working with precise circuit, you do not need to remember them.
In this short article, we considered only usage of ceramic capacitors in direct current (DC) circuits within the range of 12V to near zero. This range is common for the hobbyists. For professional usage, it is practical to know the tolerance marking system too.