Capacitor electrolytic blown

Blown electrolytic capacitors indicate circuit failure, often due to overvoltage or aging.

About this subject

Electrolytic capacitors are polarized components that store electric charge using a thin oxide layer as dielectric. They are widely used in power supplies to filter noise and stabilize voltage. Typical lifespan is around 2000 hours at 85°C, but higher temperatures significantly shorten that period.

When an electrolytic capacitor fails, the top often bulges or ruptures, releasing flammable gas. This happens due to overvoltage, reverse polarity, excessive ripple current, or simply aging of the electrolyte. The electrolyte is a conductive liquid that can cause short circuits or corrode PCB traces if leaked.

Visual signs of a damaged capacitor include a bulged top, broken vent, dried electrolyte residue, or stains on the board. In severe cases, the capacitor may pop, scattering debris. Replacement should be done with a capacitor of equal capacitance, voltage rating, and type, respecting polarity.

Frequently Asked Questions

What causes an electrolytic capacitor to explode?

Main causes are overvoltage, reverse polarity, excessive ripple current, or natural electrolyte aging, which builds up internal gas pressure.

How to identify a damaged electrolytic capacitor?

Visual signs include a bulged or cracked top, electrolyte leakage, stains on the board, and a distinctive smell. With a multimeter, capacitance may be low or ESR high.

Can I replace a blown capacitor with one of higher capacitance?

It is not recommended. Use the same capacitance and equal or higher voltage rating, same type (electrolytic, low ESR, etc.), and respect polarity.