Finding a Replacement Electrolytic Capacitor
Typical surface mount aluminum electrolytic capacitor
Anyone doing board-level troubleshooting typically starts out by checking the capacitors. Capacitors are the most commonly occurring electronic component used within the industry. While there are many types, shapes, sizes, and specifications, this article will focus on aluminum electrolytic capacitors and how to properly cross them.
The first step to finding a cross is identifying the bad capacitor, and correctly reading the specifications printed on the top or side of the capacitor. Most, if not all, will have the capacitance, voltage, some sort of manufacturer marking, and a designator for the negative lead/pad if polarized.
Capacitance is denoted as μF on aluminum electrolytic capacitors whether it’s labeled or not. The voltage will sometimes be labeled “V”, clarifying what the number is. Surface mount will often have a code to represent the voltage. Please click here for more information on how to decipher these codes. One other piece of information that might be given is the temperature rating in degrees Celsius. It can visually be deciphered if the capacitor is through-hole, with wire leads protruding from the bottom (or each side if axial), or surface mount if there are pads on the bottom of the component.
One issue people often run into when crossing these is that they do not select a range of voltages. It is ok to select a capacitor with a higher voltage rating than the original, as it will only charge and discharge as necessary in the circuit. To be safe, never select one with a lower voltage unless you know the circuit is designed to handle it.
Differing lead spacing on a through-hole capacitor isn’t detrimental in most scenarios if they are similar, because the leads can be manipulated to fit. This needs to be determined by the user on a case-by-case scenario. If the capacitor is surface mount, make sure to measure the spacing so the pads line up with the board.
Now that all the necessary specifications have been defined, please watch the video below for a demonstration of how to cross a capacitor on Digi-Key’s website. There are a few tips and tricks that will help ease the user’s search efforts in general, and just navigating the website as well.
For further discussion, join our Forum topic. https://forum.digikey.com/t/finding-a-replacement-electrolytic-capacitor/1709