Asked — Edited

Power Supply Question

Hi all, In my unpacking of items I've gotten out of storage, I've found an old kyrocea power supply. It says output is 5.2vdc. If I cut the end off and replace it with a proper connector, will I be able to use it for bench testing? I'm assuming I would but being new to electronics, I'll be second guessing myself until I get more experience.

Thanks in advance.


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How many amps does it give out? Voltage wise it should be OK just about. Current wise, if it gives out enough to supply whatever is attached - I use a 2A 12v DC PSU for bench testing and it works great.


400mA? That's milliwats correct? So that's less than 0.5A. Now I'm guessing it would not be enough? Let me ask a better question. What would be too much before I overheat or damage the board?

I think I have some power supplies that are 12v DC and various A ratings. I know I have a 3A so that isn't enough but I think I have a 6 or 7 and a few 9s. I probably about 10 power supplies floating around from stuff I don't have anymore but for some reason I felt the need to keep all of the power supplies.

Thanks again:)

United Kingdom

millamps yes (1A = 1000mA), so probably not enough to do much.

As high a current as you can find since only what is required is pulled, kinda like gas in your car's tank (volts are like the engine).

For voltage, anything between around 6v to 12v wont cause the EZ-B to get too hot, it can take up to about 17, 18, 19v (I forget which, it's up that way though). But if it's bench testing I'm assuming the EZ-B wont be enclosed so heat shouldn't be too big a deal, and throw on a fan (a small PC fan works perfectly).

As I said, I use a 12v 2A supply and this works OK. It wont work great for big loads like a few high torque servos and a bunch of lights but for the most part it's done well.

No need for anything above 5A since the EZ-B regulators are only 5A. So the best, something between 6v 5A, 12v 5A 9v 5A. Minimum I would say 6v 2A


Thank you Rich. No luck finding one laying around so far but at least I know what I'm really looking for now;)


Old computer power supplies are great for bench testers. Lots of amps you can pull and they will give you at least a 5vdc and 12vdc feed.

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My old router had a good one on it:) No idea why it was 2A output but it was.

DVD players are good too from my experience (I horde power supplies too)


Ahh thanks for the tip. I may have some old DVD player supplies in the chaos. I actually went to look at an old router I had but it was not enough.

Thanks dschulpius, I may have one of those too. I really don't remember what I had in storage so going through it has been a nice trip down memory lane. But still not anything I'm really looking for. Except for my ball point pen/laser pointer combo. I loved that thing. It needs ink but I found the extra set of batteries and it works great:)

United Kingdom

Good thinking Dave, I hadn't thought of that one. If you have an old ATX supply then forget about anything else:) Josh did a tutorial on it in the showcase too, pretty simple to set up.


Thanks Rich.

Old ATX power supplies require a load on the 5+ (sometimes the 3.3v also if it has one) before it will start up. You can simply add a jumper between any green and black wire to trick it into thinking it has a load. Then just plug it in and flip the switch (if it has one) and you have power. :)

Green to black is 5vdc Green to yellow is 12vdc

Test for proper power voltage before adding any load. Don't want any surprises. eek

If you don't have voltage remove all connections (except the load jumper), check your wiring and try turning it off and on again. Sometimes they shut down if they sense a short of over voltage.

Have fun, Dave Schulpius


I'll have to see what surprises the storage gods bring me. Thanks for all of the info on options.:)


Be careful using switching power supplies (such as found in computers). Often, if the load is too small they do not regulate the voltage very well and it could go high enough to damage parts. A single microprocessor does not draw enough current to stabilize large switchers. A load resistor and a 'ON' indicator light can be used to provide more current draw if required.