Adjustable Circuit Breaker

Tired of having to replace fuses for your projects? Different projects require different current ratings? Then you should build this circuit!

All you need is

  • 1x Voltage Comparator(Like LM311) or an Opamp make sure that they are compatible with a single supply
  • 1x Shunt Resistor(use 1 ohm if you are planing on using panel voltmeter(the voltmeters should be around the expected current measurement)
  • A potentiometer for adjusting the maximum current, it is used as a variable Voltage Divider. its voltage equals maximum current to which if greather than or equal to the voltage it will turn the project off.
  • Normally Closed for the reset button
  • Normally Open for turn off button(NOTE: CURRENT STILL FLOWS WHEN TURNED OFF/TRIPPED).
  • A NPN transistor, relay and snubber diode.

The relay acts as the switching element which can turn off the project when too much current is drawn. The voltage comparator/Opamp compares the voltage and outputs a logic 1 or 0 depending on how much more the voltage is on the positive input and negative input pins.


figure 1 Schematic

Published by Justin Roeder

I am an electronics engineer and computer programmer that has autism. I learned by myself

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