Instructables

What is and how does a Zener Diode work?

I have looked it up, and was utterly confused. Can a helpful somone from the Instructable community explain?

A Zener is not like a normal diode. A normal diode lets current flow in only one direction and needs to be installed in the correct direction. A Zener diode is placed in the opposite direction, against the flow of current. A Zener diode will prevent current from flowing until it reaches a certain voltage, depending on the diode rating. Once this critical value is reached, current is allowed to flow. The diode will also try to keep the outgoing voltage at its rated level, say 5 volts. If you feed 10 volts through the diode, the voltage might climb to 5.5-6 volts, but it will try to stay at the same voltage. If you feed too high a voltage through the diode, it will break down and fail.
I think I know what you are wanting it for, so im going to give you that answer. basicly, if you run a high enough voltatge through it it gets hot and lights fuses. it does work, ive done it. sorry if thats not what you want.
It wasnt intended for a step mine, however that knowledge is useful! -PKT
it didn't have to be a step mine, it could be remote detonator, tripwire, anything with electricity. oh, and if thats not what its for, what do you need it for?
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Zener diodes are still validly used in voltage regulation--the idea is to keep a minimal current flowing so that the rest of the regulator circuit has a target reference. Without Zener diodes "chopper" power supplies (as found in PCs) would ramble all over the place and cook MoBos and CPUs.

If you want something to get hot and use as a "fuse", torch bulbs are much cheaper.
megapix5 years ago
A regular diode conducts electricity in one direction, but won't let current pass in the other direction until a high "breakdown voltage" is reached, for example 50 or 100 volts. If the reverse current is limited by a resistor or other means, the breakdown isn't necessarily destructive, but the exact voltage isn't specified. A zener diode is designed so that the breakdown occurs at a lower voltage (such as 5.1V, as shown in seandogue's schematic), and the diodes are sorted so that you can buy one that will "break down" at the voltage level you need, after which the voltage across the diode will remain relatively constant even if the current changes over a wide range. The current still has to be limited so that the power rating of the zener is not exceeded. A zener diode is used to provide a known voltage level in a circuit (if you don't have a voltage regulator i.c. providing the level you need).