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A Zener diode normally starts conducting current when the voltage applied across its terminals rises over a certain threshold, called the Zener voltage. After this threshold the current keeps increasing.

Is there an electronic device / component which stops conducting current if the voltage goes above over a certain voltage? Or a circuit (simple as a Zener diode) with this function?
I know that will be unlikely to conduct an infinite current at zero voltage.

Circuit fantasist
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fjohn
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    Specifically voltage? Not a single discrete device. Well, there is a JFET or other depletion mode device but those are 3 terminal. – DKNguyen Jun 11 '21 at 14:09
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    How can this work? If the device is conducting, then the voltage on it is ~zero, so how can it go higher? – Eugene Sh. Jun 11 '21 at 14:10
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    With two (or more) devices sure. One single? An PTC behaves slightly in the way you describe, low ohmic at low voltage and higher (but in no way fully off) at high voltage. – winny Jun 11 '21 at 14:11
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    MOV? TVS? Crowbar? Active clamps? PTC? Fuse? Active current limiter or CC source. – Tony Stewart EE75 Jun 11 '21 at 14:11
  • @TonyStewartEE75 OP wants the opposite: Detects high voltage and opens the circuit. – DKNguyen Jun 11 '21 at 14:12
  • perhaps a fuse? although not quite, that's current operated. Something like a polyswitch ? (actually, if you don't mind it operating a bit slowly, and only once - a resistor ...) – danmcb Jun 11 '21 at 14:12
  • @EugeneSh. Certainly not. A resistor conducts down to infinitely low voltage and the voltage across it can certainly go higher. – winny Jun 11 '21 at 14:15
  • Some say Zenner but I say Zeener however it is spelt Zener – Tony Stewart EE75 Jun 11 '21 at 14:15
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    This older case has some easy to build circuits you maybe could use: https://electronics.stackexchange.com/questions/435418/what-is-the-physical-meaning-of-negative-resistance At least one of them does something which resembles what you described. –  Jun 11 '21 at 14:16
  • @DKNguyen I was intending to show other means of interrupting Zener current with a bypass clamp – Tony Stewart EE75 Jun 11 '21 at 14:16
  • @TonyStewartEE75 Oh, I see. – DKNguyen Jun 11 '21 at 14:17
  • @winny I presume the OP is interested in a device with very low dynamic resistance similar to Zener diode – Eugene Sh. Jun 11 '21 at 14:17
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    A Gunn diode won't become an open circuit, but its current drops when voltage exceeds a threshold. – Theodore Jun 11 '21 at 14:18
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    Poor specs. Define voltage, current, risetime , duration and reaction time to stop current and voltage , surge rating of Zener. There exists a SOA, but you need to define what needs to be protected more than just “a voltage threshold” – Tony Stewart EE75 Jun 11 '21 at 14:26
  • @EugeneSh. Well aware. I was just pointing out that conducing and voltage go higher are not mutually exclusive as you asked it. – winny Jun 11 '21 at 15:59
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    Specs: Voltage 5V (the threshold ), current : miliampers (<10 mA), Risetime, duration, reaction : not important (lets say for 50Hz) – fjohn Jun 23 '21 at 12:29
  • Related but not necessarily what you want: https://electronics.stackexchange.com/a/452533/17387 – try-catch-finally Sep 18 '21 at 13:40

3 Answers3

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It's not too hard to design a circuit that opens up (to some finite voltage) if the input exceeds some limit and "passes through" lower voltages, but such a circuit will not be as simple as a single device or two unless someone has already integrated it onto a chip.

I'm assuming it would essentially require three terminals (one to sense the voltage and two more for current in and out) rather than two terminals like the Zener ('Zeenah' if you want the more Germanic pronunciation, though Zener was born in the US) diode.

Note that such diodes above around 5-6V depend primarily on the avalanche effect, not the Zener effect (and it was not discovered by Clarence Melvin Avalanche).

Spehro Pefhany
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Such an "AntiZener diode" (circuit) can be made by two elements in series - an opposing diode and opposing voltage source.

The name of this circuit is "diode limiter".

Circuit fantasist
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“I know that will be unlikely to conduct an infinite current at zero voltage”

But a crowbar after a fuse will conduct all the current at any voltage. (Limited by loop resistance)

Please be more specify on what protection is needed and why.

Tony Stewart EE75
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