Pocket Power Supply

This is a pocket sized power supply with a 9 volt input and a selectable output voltage. The output can be set in 1.5v intervals (1.5, 3, 4.5, 6) to mimic one to four 1.5V batteries.
This little supply can be used at garage sales, flea markets and thrift stores to test electronics before you buy them.


charleszamzow (Aug 10, 2016)
I had the same problem. Apparently modern 9 volt batteries are too thick for the enclosure supplied. I sanded the inside of the enclosure and the enclosure lid, and I installed a regular 9 volt battery clip just soldered to the supplied batter connectors, and I got the lid to fit, almost. At least it is usable this way. There are two problems. 1, the battery is too thick for the enclosure, and 2, the supplied battery connectors, when used, make the battery too high off of the enclosure floor. That is why I installed a regular 9 volt battery clip (to get the battery all the way down in the case. I don't know what caused the problem. Maybe the enclosure has shrunk in size, or maybe batteries are now thicker.
msalley (Sep 21, 2015)
I put this together and found that the top will not go on with battery inside. Any thoughts? Frustrating. Even without the circuit the battery by itself barely fits. I removed the internal post inside the project box.
I clipped the leads to wires as close to the board as possible.

The circuit works great! Tested with a multimeter and then a blue and a red laser diode. Nice.