Re: update

On 4 Oct 2006 09:10:09 -0700, "randomname" <randomname12345@xxxxxxxxx>
wrote:

Today I purchased a wall transformer from the dollar store (liars -- it
was $3.59) that has 1.5, 3 4.5, 6, 9, and 12 volts, and works with 110
or 220 volt inputs, and provides 500mA of current.

So this replaces my 4 AA batteries, which would run weak after a couple
of hours. Strange thing is, when set to 6v it really makes my set-up
go crazy. The pump pumps way more liquid, and the strobe lights just
go crazy.. they flash brightly and irradically.

So I switched it to 3v and everything is fine. Pump runs very stable,
and the LEDs are steady and bright. It's been running for over an hour
completely stable (except for the normal hiccups and jitter caused by
my crappy pump). The wall transformer is just warm (about 115 F), so I
figure it's happy.

I wonder why I need to set it to 3v. If i switch it to 220v mode, I
need to crank it up to 12v for it to run about the same. If anyone can
explain this I'm all ears.

Oh well, it works!

-sam

sounds like it's unregulated (price would suggest this too)

unregulated supplies give (say) a nominal 6 volts on load, but when
not loaded or lightly, the voltage will drift high. I have once such
supply that gives 17.5v on no load set to 12v! If this is the case
with your wallwart, then you may have been giving your thingy way more
that it was expecting (hence the higher volume pumped - the pump was
running faster)

Either:
A. put a regulator circuit in the output so that 6 volts really is 6
volts.
or
B. Leave it on 3v if all seems well
.

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