This device will protect against voltage reversal, short circuit, low voltage and high voltage.I applied the relay to 5 Volts.With a resistor of 140 ohms, it is necessary to set the voltage at which the relay will be triggered.I got about 11 Volts.No voltage will be applied to the load below 11 volts.With a zener diode, it is necessary to set the maximum voltage at which the thyristor will work and turn off the power to the load.I put the zener diode on 14 Volts.
If the power supply is below about 11 volts, the load will be de-energized.If the power supply exceeds 14 Volts, the load will also be de-energized.When powered from 11 Volts to 14 Volts, the current will go into the load
