A favorite project of ours is the humble breadboard power supply. Yes, you can still prototype on breadboards, no, you don’t need an entire bench power supply to prototype on one, and every breadboard made in the last forty years has had the same pattern of holes. There’s plenty of opportunity to improve the breadboard power supply.

One of the best ones we’ve seen yet comes from [John Loeffler]. It’s a simple, constant voltage power supply that’s variable from 0.6 V all the way up to 12 V. It’s powered through a micro USB port, and you get 3.3 V and 5 V rails automagically. There’s even voltage indication.

The mechanical design of this power supply is simple enough, with pins that plug into the detachable power rails on either side of the breadboard. Where it gets interesting is the voltage indication. There’s a resistor ladder and a series of LEDs to indicate the voltage on the variable side of this power supply. Add in some modern switched mode power supply based on the MIC5225 series of chips (a popular regulator that’s very nice for the price) and you have a completely functional power supply hanging off a breadboard.

While it’s not a really nice rack mounted bench power supply that weighs a lot, or even one of the cheapo bench supplies, this does fulfill a need. Sometimes you just need a simple power supply for a breadboard, and this is one of the best ones we’ve seen yet.