All in one lab update

I finished the Power Supply today. Instead of using the last schematic I posted I decided to reverse engineer the HeathKit EUW-17 Power Supply. It’s very simple to build, small part count and I was able to use parts I had on hand already.


Instead of the geranium transistor that is impossible to find let aloe costs a pretty penny used I went with a 2sa1102 PNP power transistor and also used 470uF caps instead of 500uF, I’ve never seen a 500uF cap anyway. The transformer is a small one that I pulled from a printing calculator. It has two secondaries so I plan to use the second set as a fixed regulated 5volt supply. The diodes for the rectification are 1n5402. I’m currently using a 10K pot but it works just as well. The resistors are 1/2 watt.

Here is my updated schematic.


The fuses depend on the output of the transformer. However for the second fuse on the output I would use a 500ma or use a beefy diode to add protection.


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