What happens if a capacitor arcs?

If the arcing occurs between a termination surface and through the dielectric material of the ceramic body to the first internal counter electrode, this usually causes a dielectric breakdown of the capacitor, resulting in a short-circuit condition that leads to catastrophic failure.

How can a capacitor prevent arcing?

Capacitor vendors have tried a number of approaches to prevent arcing. One of these is to apply a polymer or glass coating along the surface of the chip to fill any voids and provide a smooth surface that has a naturally lower susceptibility to creepage.

How does a conductive capacitor work?

Once the inception voltage of the ionized air is reached, a conductive path is created, allowing the energy in the concentrated electric field of the termination area to discharge. This discharge travels through the air along the surface of the capacitor and onto an area of lower potential rather than through the capacitor.

How a RC network is placed across the contacts in an arc suppression circuit?

To prevent this phenomena, an RC network is placed across the contacts. Arc Suppression Circuit Calculation Explained 1. When the contacts in an arc suppression circuit open, the applied voltage is placed across the capacitor and not the contacts.

How do arc shield ceramic capacitors work?

ArcShield ceramic capacitors address these failure mechanisms by adding a shield electrode, which prevents arcing between terminals and any nearby opposing electrode. The devices also incorporate thicker active areas that effectively increase the breakdown voltage.

Why do capacitor terminals have a shorter distance?

The shorter distance between the device terminals will bring about reliability concerns due to a greater risk that creepage — the natural tendency of an electric field to spread out over a dielectric surface — may allow arcing between the capacitor terminals ( Fig. 1 ) when the full working voltage is applied.