A crowbar circuit is used to product a circuit from a too high voltage. When the voltage gets too high, a device will short circuit. This results in the current flowing parallel to the circuit. This causes immediately a voltage drop in the circuit. The high current through the shunt should trigger a circuit breaker or a fuse.
Sometimes Microhm's shunts with a capacitor are applied in circuits where high-frequency noise is a problem. The capacitor redirect the noise to the ground before the undesired signal reaches the circuit elements,
When one element in a series circuit fails, it will break the complete circuit. A shunt can be used to overcome this problem. The higher voltage that exists due to the failure will cause the shunt to short out. The electricity will pass around the defective element. A good example of this is Christmas lighting which are wired in series. When the filament burns out in one of the incandescent light bulbs, the full line voltage appears across the burnt out bulb. A shunt across the burnt out filament will then short out to bypass the burnt filament and allow the rest of the string to light. If too many lights burn out however, a shunt will also burn out, requiring the use of a multimeter to find the point of failure.
Microhm Electronics Ltd. is a leader in custom shunt resistors. Welcome to contact us for more details at any time.
