In our previous post, we discussed how to decode capacitor markings in colour. Is not it interesting? Try something more. In this post, Let’s learn how to decode capacitor markings in number.

How to decode Capacitor markings in Number format :

Mostly, ceramic capacitors come under this category. In normal practice, Ceramic capacitor has a three digit code value on its body. Kindly note that the decoded value of a Ceramic capacitor is always measured in Pico farad (pF).

Now, let’s take an example to understand it more easily. Suppose, we have to decode the capacitance value of the below mentioned capacitor.

Example of a Ceramic Capacitor

The three digit code of the capacitor is 681J. Here, The first 2 digit code gives us the starting capacitance value of the capacitor and the third digit says how many zeros we have to add in it to get the actual capacitance value. If there is a letter code after three digits, it denotes the tolerance value of the capacitor. If there is no letter code, then the tolerance value is unknown.

Thus, we can easily identify now that in case of capacitor 681J, the first two digit 68 means “the capacitor has starting capacitance value of 68”. The third digit 1 means “the number of zeroes behind 68 will be one” i.e . the capacitance value will be 690 pF.

Now , the tolerance as per the letter code is as tabulated below:

Thus, we can easily identify now that in case of capacitor 681J, the last letter code J means “the capacitor has a tolerance limit of ± 5 %.

Coming to the conclusion, we can now easily decode capacitor marking (number) of most of the capacitors. Here, capacitor 681J means “it has a capacitance value of 680pF± 5% tolerance.

In some case, we will see only a decimal value written on it. Suppose the decimal value written on the body of a capacitor is 0.01. Then this is the capacitance value in pico Farad. We do not have to convert it.