Overvoltage Protection Circuit

Posted on Feb 7, 2014

An overvoltage protection circuit is a circuit which protects electronics from excess voltage, which could potentially damage or destroy electronic components. In this project, we will build a simple, yet effective, overvoltage protection circuit using a fuse and a zener diode, as the protecting elements, that will work for electronics that operat

Overvoltage Protection Circuit
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e with DC voltage. The zener diode that you will choose depends on how much voltage you want to limit the circuit to. Zener diodes are rated with all differing amounts of breakdown voltage ratings. The breakdown voltage is the amount of reverse voltage which a zener diode can receive before it breaks down and begins conducting reverse current across its junctions. A zener diode will not conduct current across its terminals unless this threshold breakdown voltage is reached. Before the threshold voltage is reached, zener diodes will simply "hold" the voltage across its terminals that is exposed to. For example, if a zener diode is rated for a breakdown voltage of 12V and it is exposed to a voltage of 3V, it will simply hold the 3V across its terminals and not conduct any current across its terminals. If the voltage reaches above 12V, then the zener diode will break down and conduct current across its terminals. Therefore, use the zener diode with a voltage rating that you want to limit your circuit to. If you want to limit your circuit to 5V, then use a zener diode with a breakdown voltage rating of 5V. After this 5V threshold is reached, the zener diode will conduct current across its terminals and shunt excess power to ground. If you want to limit your circuit to 12V, then choose a zener diode with a breakdown voltage rating of 12V. After this threshold is reached, the diode will break down and shunt all excess power to...

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