Why Do Capacitors Bulge? Causes and How to Prevent It
If you've ever opened up a TV, monitor, or power supply and noticed a capacitor with a domed, swollen top instead of a flat one, you've found your problem before you even ran a single test. A bulging capacitor is one of the clearest visual signs of failure in electronics, and it's also one of the easiest to miss if you don't know what you're looking for. Here's what actually causes a capacitor to bulge, why it matters, and what you can do to stop it from happening again. What a Bulging Capacitor Actually Looks Like Most electrolytic capacitors have small pre-scored vent lines stamped into the top, usually in a K, X, or + pattern. On a healthy capacitor, that top is flat. On a failing one, internal pressure pushes that top upward into a dome shape, sometimes cracking along the vent lines. In more advanced cases, you'll see dried electrolyte residue crusted around the base, or the capacitor may be visibly leaning. If you spot this on a circuit board, it's...