Bench Power Supply Adapter


Every electronics workbench could benefit from having a bench power supply. Converting a PC power supply works, but often, it involves splicing wires and limits the supply to only bench use, and building one from scratch is definitely an undertaking. To counter this, [silic0re] and his father came up with a detachable adapter that simply plugs into the existing connectors. The adapter provides posts for four different voltages and can be built in no time. It’s nice to see a solution that will let you use any power supply laying around without having to worry about the dangers of opening it or cutting it up.

[Thanks silic0re]

14 thoughts on “Bench Power Supply Adapter

  1. as to the possible need of a load resistor some power supplies do need one but most do not. If the power supply is known to be good and it will not power up add a 5 watt 30 ohm resistor between the +5 volt line and the common to correct the problem.
    The cost is about a buck.

  2. Switchers won’t work without some kind of minimum load. Depending on the supply, that load has to be on both the 12v and 5v. You also have little issues with signal wires like ‘pwrgood’.

    All these can be built right into the benchtop box, however, with no trouble.

    All in all, a useful tool and an extraordinarily simple implementation. Neat hack.

  3. A good way to load up a power supply is a light bulb. Not an LED, a regular light bulb, buy a 12v light bulb for a car for example. Radioshack also has 5v light bulbs. Besides loading up the power supply, they will surve as a nice “power” indicator. Another neat thing I used to do is buy Radioshack analog ammeter and wire it in series so that I always have a load indicator. you can see if something is wrong if all of sudden your starting to pull 3-5amps of power through something that should be using 100mA. Indication of a short or leakage somewhere.

  4. roman: An ammeter shunt can cause significant voltage drop. My roommate an I hacked together a 4-bit processor out of TTL in college (1980’s), which mysteriously stopped working just as were added the last circuits. Turned out to be the ammeter, and our little computer lived for a few glorious days before we had to return the borrowed proto board.

  5. You can also get one by chopping an ATX extension cable in half, of course. A little bit neater.

    I’ve just popped out to get the banana plug terminals to build myself one of these.

  6. @ken true, for devices that use a very small amount of power it could cause issues. Besides heat decipation and fact that your sensing equipment is directly coupled to the measured part. A better alternative in many ways is a hall effect sensor, they are capable of measuring both DC and AC currents and you get a benefit of isolation.

  7. Ive often contemplated making one of these. The thing that kept me from doing so was since i started making USB devices I made a little breadboard module (tiny pcb with 3 pin 90o header) with an MCP1700 3.3v LDO and 2 caps. I also built a little regulated 5v one. So now when a project needs power Ive got options:
    1. use a usb connector to get dirty 5v
    2. use a 9volt to get 5 volts (portable)
    3. use the 5v above to get 3.3 v
    4. Use 9volt battery eliminator (wall wart) to get 5v
    I think in total it cost me about 5ea$

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