cb

This circuit uses a 555 timer to detect the event of overcurrent. The trick is that the current drawn by the load makes the voltage on 555's VCC drop. Inside the NE555, there is a comparator that compares THR and VCC. We can then set the voltage on THR with the potentiometer. If the load draws too much current, the voltage on VCC will drop below the voltage on THR, and therefore trigger the ouput. Instructions to use included in the schematic.