Electronic Circuit Breaker Circuit with Low / High voltage Protection

In various condition the grid line voltage will fluctuate and it will kill our home appliances and also reduces the life any electronic systems. In this case we can not know in which time the voltage fluctuations happens. The normal home appliances like Toaster, Televisions will not withstand in higher voltage. so i’m introducing a simple electronic circuit breaker circuit for you.

This circuit breaker project working based on the IC LM358 op-amp. This entire circuit diagram will continuously monitor the input AC voltage in any cases of Over voltage or Under voltage the circuit will trigger the Relay to turn of the connected device’s.

Electronic Circuit Breaker circuit

The Complete Schematic diagram of the Electronic Circuit Breaker is given below. Read further for to know the working and its explanations.

Electronic circuit breaker circuit diagram
Electronic circuit breaker schematics

Components Required

  • LM358 ( Dual op-amp IC )
  • 7805 ( 5v voltage regulator )
  • 12v Step down Transformer
  • 5V Relay 10amps
  • BC547 Transistors ( 2 Nos )
  • 10K pot
  • 1K,2K,2.2K,10K and 5.1K Resistor
  • 0.1uf, 100uf, 10uf capacitor
  • Bridge Diode
  • Connection wires

Electronic Circuit Breaker Working

As shown above circuit diagram The simple electronic circuit breaker, Really contain few numbers of electronic components in this circuit diagram. i am explaining the working of each of part in the circuit diagram below.

Input Power Supply Section

Electronic circuit breaker power supply section
Circuit breaker power supply section

LM358 is the heart of this circuit diagram. so we need a regulated power supply to turn on it. so a 12v transformer is using to provide continuous 12v dc then it will regulated to 5V.

  • So the above circuit will clarify that the transformer will convert 220v AC to 12V ac supply.
  • Then the 12V ac supply has to be rectified through the combination of 1N4007 bridge diode and a 1000 uf filtering capacitor.
  • Then the 12v DC injected to LM7805 Ic then it will convert it in to 5V Dc for LM358 IC supply.

Op-Amp Circuit

Electronic circuit breaker op amp section
Op amp section

In this Op-Amp circuit section total voltage comparison is occurring. The two subdivisions of op amp is noticeable. One section is used to compare the ” current voltage ” and the other one is is compare the “low voltage value”. both sections are shown in the above image.

The voltage comparator in this case the voltage between the pin 3 and 2 is comparing. If the voltage of the pin 3 is greater than the voltage of pin 2 then the output voltage of the op amp section is high like output voltage is 3.6v, else the output voltage will be zero.

In this circuit diagram the low voltage cut off is set by 1K and 2K resistors. Also the high voltage threshold is set by the Pin 5 using 1k and 2.2k resistors.

Relay Control Section

Electronic circuit breaker relay section
Relay section

If the both op-amps will operate the relay circuit. In the case of Low voltage and High voltage condition the op amp will trigger the voltage signals and it will be turn off the BC547 transistor. in that condition the home appliances will get protected.

Once you understand the working of this circuit it is not a problem to build your own.

Also check Latest Projects By soldering mind below.

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