Hi Nigel, Gerty, Sebi, jrz126,
Yes, usually the supply is labelled up, but on this little hub its not.
The only reason i know its an AC feed is cos i've had it apart, and its
fed straight to a diode bridge.
Anyway, i tried it again, and cos i know roughly the voltage its ok at
from before, i already had it set to seven volts when i switched on the
supply, which looked a bit lower current draw than before although the
lights all looked normal.
So i varied the supply a bit up and down. I was most surprised and
pleased to see that the current draw was less as the voltage went up,
and more as the voltage went down.
This was the behaviour i had expected to see before, but i had been too
cautious before, as i found now, that if the voltage is wound up from
nothing the circuit just takes more current with rising voltage, but
if you switch on an applied voltage between seven and twelve volts
the circuit works as i think it should.
I found the maximum current draw to be @ 95mA at @ 8v falling to @ 50mA
at @ 12v, i did not push it higher than 12v cos i dunno the cap ratings
but it looked like it may have used a little less current if i had.
So i have now seen this peculiar 'buck-effect' for myself.
I am now poking around amongst my collection of small transformers to
find one that i think will be suitable for this little hub.
I am guessing that a small 6.3v transformer would give a suitable voltage
after smoothing, about 8.5v roughly ... ?
Still looking.
Regards, John