dummy load

Another afternoon project. Some time ago I was working on a 80 watts 12-to-36 Volts DC-DC boost converter. Not one of my most successful projects but anyway. So I needed some kind of load but my home made constant current dummy load can only handle 20-something volts. A few 100 ohms 15 watt resistors were just what I needed. So I took 6 of them and made a simple, single-sided PCB that holds the resistors as well as 6 switches.

This is a constant current dummy load. It’s controlled by a PIC16F1936 microcontroller. As you can see, it’s equipped with a 4x16 character LCD display and, less obvious, a rotary encoder with push button. It accurately sets the desired current via a 16bit DAC and reads both current and input voltage with a single-channel 16bit ADC each. Temperature is measured by the microcontroller’s internal 10bit ADC.