A classic afternoon project. I was in need of a variable voltage and didn’t have a proper lab power supply available. But I did have a solid 12 volts from an old computer PSU. So I built myself this little thing.
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.
