This is a programmable current sink, usually used to simulate different current loads for power supplies. We have always wanted to build one, but we’ve stalled several times. This design is based on the simple analog load posted by Bearmos. It’s not intended to be a final project, it’s just an experimental prototype to see what might go into an eventual project.
We’re using an MCP4725 I2C 12bit digital to analog converter to set the current instead of a pot. Everything is controlled via the USB capable PIC18F2550 microcontroller, The relevant data is displayed on a 2X16 character HD44780 LCD. The UART interface is also available for datalogging and debugging. You can check out the schematic below.
This is only a initial test version, as we plan to develop this project more. If you have any suggestions, tips, or questions please head for the forum.