Electrical

Crowbar Protection: Sacrificing Fuses for ICs

Electrical Diagrams · made in Skemio

Schematic of a 12V DC line with a fast-acting fuse feeding a protected load, alongside a Zener-triggered crowbar shunt path.
Schematic of a 12V DC line with a fast-acting fuse feeding a protected load, alongside a Zener-triggered crowbar shunt path.
Open it in SkemioMake your own

What it shows

  • A Zener detects overvoltage and fires an SCR gate in microseconds.
  • The SCR intentionally shorts the main DC rail straight to ground.
  • Heavy short-circuit current quickly blows the upstream fuse.

The takeaway

Blow a cheap 50-cent fuse immediately rather than cooking expensive microchips.

More electrical diagrams