With the zener diode voltage chosen to be slightly above the maximum rail voltage under normal conditions it will not conduct.
Over voltage protection circuit power supply.
Another very simple form of over voltage protection uses an approach called voltage clamping.
For protection from high voltage surge we always use overvoltage protection or crowbar protection circuit.
Over voltage protection is a power supply feature which shuts down the supply or clamps the output when the voltage exceeds a preset level.
This is a sequel to our anatomy of switching power supplies tutorial and we are going to explore in depth all power supply protections like over voltage ovp under voltage uvp.
Most power supplies use an over voltage protection circuit to prevent damage to the electronic components.
In its simplest form it can be provided by using a zener diode placed across the output of the regulated power supply.
In some situations where the input voltage is higher than expected we always use an overvoltage protection or crowbar protection circuit.
When the power supply voltage increases too much a thyristor shortcircuit the output.
The circuit has a few components it is very easy to build and will protect your electric equipment againg overvoltages.
The crowbar circuit must be mounted between power supply and the protected device.
Crowbar protection circuit is a type of overvoltage protection which is most commonly used in electronic circuits.