Is there such a thing as a inverse varistor?

[kmarinas86]

Is there such a thing as a "inverse" varistor?

Is there a type of electric component that will create a short circuit once the voltage exceeds some specified value which it has been rated at, regardless of what end the voltage appears at?

 

[Bob S]

Triacs can be triggered to turn on at any programmed gate voltage, with either polarity. They will not turn off until the current is removed. See http://en.wikipedia.org/wiki/TRIAC

Bob S

 

[Carl Pugh]

A negative temperature coefficient thermistor decreases in resistance as it's temperature increases. However the resistance never goes to zero.

There is one company that uses a capacitor that shorts when the voltage exceed the capacitor's rating.

 

[berkeman]

Is there a type of electric component that will create a short circuit once the voltage exceeds some specified value which it has been rated at, regardless of what end the voltage appears at?

Why is that inverse? That's how MOVs work, AFAIK.

 

[Averagesupernova]

Why is that inverse? That's how MOVs work, AFAIK.

I would agree with berkeman. There is a thyristor device that didn't gain a lot of popularity because MOVs took over. I forget what it is called, but it is like an SCR without the gate lead. I believe it can be made to be bidirectional. It relies on breakover voltage to conduct and will continue to conduct until the current through it approaches zero.

 

[AlephZero]

This type of circuit using SCRs was (probably still is) used in some applications as a "last ditch" protection device, the idea being that it puts a short circut across the input power supply, to guarantee that all the fuses blow and/or the circuit breakers trip.

They were usually called "crowbar" circuts, by analogy with jamming a big iron bar into a piece of machinery to stop it regardless of how much collateral damage occurs.

 

[Studiot]

Why is that inverse? That's how MOVs work, AFAIK.

I agree with Berkeman.

MOV devices are used as lightning and other surge arrestors for exactly this purpose.
One point to not is they are 'one time' components.That is they have to be replaced after they have acted.

A straight forward avalanche diode also offers the desired characteristic and is reusable if the short circuit current is limited to a suitable value.

Also on the list might be fusible resistors. These are also one time devices, often employed in switching power supplies. These are really overcurrent devices, but Ohm's law enables that to be recast as overvoltage, with suitable circuit configurations.

If, of course you actually meant a device that tuns off rahter than on by inverse then how about a gate turn off device (GTO)?