Nathan House wrote:
> I'm burning through batteries like nobody's business and think it's
> high time I purchased a power supply. I know I can make my own board
> with voltage regulators for common voltages like 3.3, 5, 12, etc, but
> I think I'd rather have something that's adjustable and can source a
> lot of current in case I ever need it. I've been looking at power
> supplies on ebay and stumbled across a very low price one that seems
> to be pretty popular (the seller has sold 159 of them):
>
> http://www.ebay.com/itm/Precision-Lab-PS305D-Variable-30V-5A-DC-Power-Sup=
ply-/120716204084?pt=3DLH_DefaultDomain_0&hash=3Ditem1c1b3f1834
>
> I've never heard of the brand before. What do you think, good buy or not?
>  =20
Note how they say "USA brand" but they are careful to avoid saying=20
anything about where it was made  I'm pretty damn sure it's a chinese=20
import and the "direct from the manufacturer" statement is probablly=20
severely stretching the truth.

I have bought some rapid own brand PSUs that have a similar style (not=20
sure if it's the same manufacturer or just ones buying their power=20
buttons and banana sockets from the same place) and they seem to work ok=20
though the meter switches can be a bit dodgy sometimes and I had one=20
(I've bought several identical ones) lose regulation on one output=20
(rapid replaced the unit but it's a worrying failure mode).

For the price it's probablly reasonable, I just wouldn't hook it up to=20
anything expensive without putting some protection in between (minimum a=20
fuse/polyswitch and a zener diode). Having said that  I would not=20
generally reccomend using any variable PSU to power circuits directly on=20
a long term basis. Too much risk of it getting set wrong. Put a=20
modernish LDO with a reasonablly high allowed input voltage (I like ths=20
LM2940 for this) on your board, run it from 6V and if someone does put=20
too much voltage in it will just go into overheat shutdown.
--=20
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