Simple Current Limit Circuit: . 5V. GND. R2. +12V. Q1 2N3904. 1K Q2. 2N3904. R1. 14. GND. This circuit will limit the current through the load to about 50ma. As before when the input to the base resistor is 5V Q1 turns on and current flows through the load. When the input is low Q1 is off and no current flows through the load. dW7Ne4A.

power supply with current limit