Capacitor Identification Guide

Capacitor Identification Guide

We recently launched our Mixed, Ceramic and Electrolytic Capacitor Kits and thought we'd create a little guide to explain how you can determine the values of the capacitors using the markings on them.


Ceramic Capacitors

These capacitors are usually very small in both size and capacitance and typically have a higher voltage rating. They're usually round or rectangular in shape and aren't polarised like electrolytic ones so you can connect them either way around.

You can calculate the value of the ceramic capacitors in our kit by markings on them. The first two digits indicate the value, the third digit is the number of 0's to add and the letter is the tolerance this then gives you the value of the capacitor in pF.

For example:

471 = 47 0 pF
103 = 10 000 pF = 10nF

 Value Marking Voltage Rating
10pF 100 200V
22pF 220 200V
47pF 470 200V
100pF 101 100V
220pF 221 100V
470pF 471 100V
1nF 102 100V
10nF 103 100V
22nF 223 100V
47nF 473 50V
100nF 104 50V
220nF 224 50V
470nF 474 50V


Electrolytic Capacitors

This type of capacitor is bigger in both size and value. They're cylindrical in shape and polarised so you'll need to ensure you place them the correct way around in your circuit. There's two ways to determine which side if positive and negative. There will usually be a white strip down the side of the capacitor which has the negative leg, just like an LED the longer leg also indicated the positive connector. Electrolytic capacitors will usually have both the capacitance and voltage ratings printed on them.

 Value Markings Voltage Rating
1uF 50V 1uF 50V
10uF 50V 10uF
22uF 50V 22uF
47uF 25V 47uF
100uF 25V 100uF
220uF 16V 220uF
470uF 16V 470uF
 1000uF 16V 1000uF
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