Hello,

someone there who can help where to find a reference for part numbering system for capacitors especially for ceramic and mylar cap.

 

If they have 3 numbers then the first 2 are the first 2 digits of the value and the last is the number of zeros to add. So, 474 would be 470,000 pF = 0.47uF.

Mike.

 

Part number conversion chart:

 

yes that is true for capacitance value, how about the working voltage on it, some capacitors marked with 2A104J in which 2A stands for working voltage of 100 volts, 104 is the capacitance value, J is the tolerance. if the capacitor marked only with 220Pf? how to find out the working voltage on it.

 

Measure the voltage that is applied in the circuit and use the next voltage range up from that?

In reality, if the cap is not marked, you won’t know it’s rated voltage – possibly its size (for a given value) will be an indication of voltage rating (higher voltage, thicker dielectric).