DIY Short Circuit (Overcurrent) Protection

In this project I will show you how to create a simple circuit that can interrupt the current flow to a load when the adjusted current limit is reached. That means the circuit can act as an overcurrent or short circuit protection. Let's get started!

Step 1: Watch the Video!

The video gives you all the information you need to recreate the protection circuit. In the next steps though I will give you some additional information.

Step 2: Order Your Components!

Here you can find a parts list with example seller (affiliate links):

Aliexpress:

1x Relay (12V one with 2 changeover contacts): https://s.click.aliexpress.com/e/_dXytThh

2x PCB Terminal: https://s.click.aliexpress.com/e/_dYbstfZ

1x LM358 OpAmp: https://s.click.aliexpress.com/e/_d6VP6J1

2x BC547 NPN Transistor: https://s.click.aliexpress.com/e/_dU81lmT

1x 5mm green LED: https://s.click.aliexpress.com/e/_dV63r7D

1x 1N4007 Diode: https://s.click.aliexpress.com/e/_dYR45Bh

1x Tactile Switch (NC): https://s.click.aliexpress.com/e/_dXIIMcP

6x 1kΩ, 2x 20kΩ Resistor: https://s.click.aliexpress.com/e/_dTPpXjt

1x 10kΩ Trimmer: https://s.click.aliexpress.com/e/_dTFyPv5

1x 0.1Ω Resistor: https://s.click.aliexpress.com/e/_dZKdSGL

Ebay:

1x Relay (12V one with 2 changeover contacts):http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

2x PCB Terminal: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x LM358 OpAmp: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

2x BC547 NPN Transistor:http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x 5mm green LED:http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x 1N4007 Diode:http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x Tactile Switch (NC):http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

6x 1kΩ, 2x 20kΩ Resistor:http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x 10kΩ Trimmer: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

1x 0.1Ω Resistor: http://rover.ebay.com/rover/1/711-53200-19255-0/1?...

Amazon.de:

1x Relay (12V one with 2 changeover contacts): http://amzn.to/2uK2t8g

2x PCB Terminal: http://amzn.to/2viTnkl

1x LM358 OpAmp: http://amzn.to/2uNMsN6

2x BC547 NPN Transistor: http://amzn.to/2vj6qCy

1x 5mm green LED: http://amzn.to/2vbPfSn

1x 1N4007 Diode:http://amzn.to/2uO2kiL

1x Tactile Switch (NC): -

6x 1kΩ, 2x 20kΩ Resistor: http://amzn.to/2uNJ4BH

1x 10kΩ Trimmer: http://amzn.to/2uKc9j5

1x 0.1Ω Resistor: http://amzn.to/2eY98qa

Step 3: Build the Circuit!

Here you can find the schematic of the circuit along with pictures of my finished perfboard layout. Feel free to use them as a reference for your own circuit.