Why might a capacitor explode under high voltage?

A capacitor might explode under high voltage due to excessive charge causing internal pressure and heat build-up.

Capacitors are passive electronic components that store electrical energy in an electric field. They consist of two conductive plates separated by an insulating material, known as a dielectric. When a voltage is applied across the plates, an electric field is created, causing positive charges to collect on one plate and negative charges on the other. This accumulation of charge is what we refer to as the capacitor's capacitance.

However, every capacitor has a maximum voltage it can withstand, known as its rated voltage or breakdown voltage. If the applied voltage exceeds this rating, the electric field can become so strong that it breaks down the dielectric material. This breakdown allows current to flow directly between the plates, leading to a rapid increase in temperature and pressure within the capacitor.

The heat generated can cause the dielectric to degrade further, and the pressure can physically deform the capacitor. If the pressure becomes too great, it can cause the capacitor to rupture or explode. This is particularly true for electrolytic capacitors, which contain a liquid electrolyte that can boil and generate gas under high temperatures.

Furthermore, the breakdown of the dielectric can also lead to a phenomenon known as dielectric breakdown, where the material loses its insulating properties. This allows a large amount of current to flow through the capacitor in a short amount of time, a situation known as a short circuit. The sudden surge of current can generate a lot of heat, potentially leading to an explosion.

In summary, a capacitor might explode under high voltage due to the breakdown of the dielectric material, leading to internal pressure build-up and heat generation. This is why it's crucial to always use capacitors within their specified voltage ratings to ensure safe operation.