Capacitor electrolytic blown

Blown electrolytic capacitor: common causes, physical signs, and impacts on electronic circuits.

About this subject

Electrolytic capacitors are passive components widely used in power supplies, motherboards, and inverters to store energy and filter noise. They feature a construction with a liquid or gel electrolyte that can dry out or leak over time, leading to failure. A blown capacitor occurs when internal pressure exceeds the casing's limit, causing a rupture in the top cross-shaped vent or visible swelling. Common causes include overvoltage, reverse polarity, natural aging (increased ESR), and excessive operating temperatures. A blown capacitor may leak electrolyte, bulge, or even explode, compromising voltage stability and causing device malfunction. In switch-mode power supplies, for instance, it can generate excessive ripple, intermittent shutdowns, or permanent damage to other components. Replacement with a capacitor of identical value and voltage rating, preferably low-ESR and rated for 105°C, is the standard repair procedure. The industry also uses polymer capacitors in critical applications for longer lifespan and higher temperature tolerance.

Frequently Asked Questions

What causes an electrolytic capacitor to blow?

Common causes are overvoltage, reverse polarity, natural aging (increased ESR), and high temperatures. Internal pressure forces the casing to rupture through the vent.

How to identify a blown capacitor visually?

Look for top bulging, open vent, electrolyte leakage (brown or yellowish substance), or deformed base.

Is it safe to use a device with a blown capacitor?

No. It can cause malfunction, power supply noise, shutdowns, or damage other components. Replace the capacitor before powering the device again.