Crowbar Circuit

Definition

A crowbar circuit is a power supply protection circuit that rapidly short-circuits ("crowbars") the supply line if the voltage and/or current exceeds defined limits.

In practice, the resulting short blows a fuse or triggers other protection, effectively shutting down the supply.

It is usually achieved by an SCR or other silicon device, or by a mechanical shorting device.

Probably named for the concept of using a big metal bar to mechanically provide the short circuit, as might be used done in a high-current application; or from the appearance of a crowbar circuit's I-V curve.