Over Voltage Electric Protector

This is the easy Over Voltage Protector Circuit Diagram. The whole circuit of over voltage protector is build and made-up around operational amplifier used as comparator. The inverting input is given to pin 2 of op-amp IC (IC1) by reference voltage of 5.1V from zener diode. Similarly, non-inverting input is given to pin no 3 of IC1 use as sensor for over voltage protector for sensing voltage fluctuation in the mains. The two transistors T1 and T2 conduct alternating (i.e. one at a time) according to the voltage of mains.

 

When voltage is around or below 240V AC transistor T1 is in off-state where T2 energized relay RL1. Similarly, when voltage becomes beyond 240V (i.e. above 240V) T1 is in conducting-stage and T2 is in off-stage which de-energized the relay RL1 and switch-off the appliance.This is way to create over voltage electric protector.

PARTS LIST

Resistors (all ¼-watt, ~+mn~ 5% Carbon)

R1 = 147 Ω/2W

R2 = 100 Ω/1W

R3 = 330 Ω

R4 = 100 KΩ

R5 = 1.8 KΩ

R6, R7 = 1 KΩ

VR1 = 10 KΩ

VR2 = 22 KΩ
Capacitors

C1, C4, C5 = 0.01 µF

C2 = 1000 µF/25V

C3 = 100 µF/25V
Semiconductors

IC1 = µA741 (Operational Amplifier)

IC2 = 7812

T1= BC547

T2 = SL100

D1, D2, D3, D4, D5 = 1N4007

D6 = 1N4148

ZD1 = 5.1V zener diode
Miscellaneous

X1 = 230V AC primary to 7.5V-0-7.5V, 1A secondary transformer

RL1 = 12V, 200Ω 1 C/O Relay