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Power Supply?

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I'm looking for a power supply to run my latest gadget (laser display with green laser and 3 rotating slanted mirrors). At the moment it uses a rechargeable battery pack "borrowed" from an old R/C car but this doesn't last very long at all. It's ok for showing it off but for longer use (ie. at parties) it needs to be wall powered. I've done some testing and these are its stats:

Input Voltage: 5v
Max. Startup Current Draw: 4.7A
Normal Startup Current Draw: 0.3A
Max. Running Current Draw: 3.6A
Normal Running Current Draw: 2.5A

I know I could buy a big transformer and build a rectifier/smoothing/regulator circuit. What I'm trying to find is a company or individual that supplies the pre-built "wall-warts". I could probably find one with the right voltage around the house somewhere but the problem is the high current draw from them.

Any advice?


PS. Transformers - what's this "VA" rating I'm seeing all over the place? :confused:
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Well-Known Member
Most Helpful Member
VA is just the product of |V| x |I|, where the || means "magnitude" without regard to phase.

You will have a hard time finding a 25VA wall-wart. You will probably have to find a "modular DC power supply", and then put it in a box. For a one-of, I would be looking for a surplus deal at one of these.

If you are going to build a linear power supply, you should be looking for a transformer that supports ~30 to 40VA. A 14V center-tapped, or 8-10V non-center tapped secondary would be about right.
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