Overvoltage protection circuit


Posted on Jul 9, 2012

The silicon controlled rectifier (SCR) is rated to handle at least the current of the power supply. It is connected in parallel across the 12 V dc output lines, but remains inert until a voltage appears at the gate terminal. This triggering voltage is supplied by the zener diode. At potentials less than 14 V the zener will not conduct current. But, at potentials greater than 14 Vdc the zener conducts and creates a voltage drop across the 330 ohm resistor that will fire the SCR. When the SCR turns on, the output lines of the power supply are shorted to ground.


Overvoltage protection circuit
Click here to download the full size of the above Circuit.

This will blow the primary fuse or burn out the transformer if there is no primary fuse.




Leave Comment

characters left:

mfarah   Apr 3, 2019

who to calculate resistances of 22 & 330 for other zener voltages?

New Circuits

.

 


Popular Circuits

PAL/NTSC Video Time/Date Generator
garden lighting
120vac lamp chaser circuit
radio controlled electronic flash
4017 led pattern flasher
Astable Multivibrator using NE 555 timer IC
LM3886 amp electronic circuit project schematic circuit
RF Field Strength Meter Circuit
Audio Power Amplifier 60W with TDA7294 circuit
LCD displays easy to use and easy to build
Flashlight circuit diagram of a motor control model
Toy police car circuit



Top