This circuit aims to use the output of a microcontroller with low current to drive a load of a high current load. Other Darlingtons can be used for larger currents. The load circuit must have an independent power supply of 6 to 18 V and the activation can be done with 3.3 or 5 V signals. The transistor must be mounted on a heat radiator. The circuit is from the book Mechatronics Sourcebook by Newton C. Braga, published in the United States.
