Thought this might be of use to someone. Here's a simple adjustable DC load, with a meter to show current draw. I wanted one of these to test power supplies. Pre-made ones are rather expensive, and I don't need most of the fancy functionality. The basic idea for this is the same as in a video by eevblog on youtube. I didn't spend much time on this circuit, but it seems to work well enough. RV2 is probably unnecessary. For higher power, I imagine one could just put more mosfets in parallel (?).
The voltmeter, mosfet, and power resistor are wired off of the board (the latter two on a large heatsink). I used an STP60NF10 for the fet. It gets warm, but seems ok at moderate power. I measured it at 70C when sinking 3A @20-somethingV. The meter accuracy seems pretty good.
My idea is that it should be powered with a 12VAC wall-wart.
Boards are here: http://www.oshpark.com/shared_projects/LwMaw4bQ (or, if anyone wants gerbers just pm). Schematic is attached.
The voltmeter, mosfet, and power resistor are wired off of the board (the latter two on a large heatsink). I used an STP60NF10 for the fet. It gets warm, but seems ok at moderate power. I measured it at 70C when sinking 3A @20-somethingV. The meter accuracy seems pretty good.
My idea is that it should be powered with a 12VAC wall-wart.
Boards are here: http://www.oshpark.com/shared_projects/LwMaw4bQ (or, if anyone wants gerbers just pm). Schematic is attached.
