On 2011-02-14, Jim Wilkins wrote:

[ ... ]

I bought the 20V 5A model (last one at $130) for a general lab supply.
Right now it's standing in for the 45W solar panels in the Harbor
Freight kit while I burn-in test the controller. Here's a link to the
HF controller schematic for those of us who speak Geek:
http://solarpanelkitatharborfreight....eight-charge-1

They don't *really* use phone jacks for the low voltage outputs,
do they? Especially the USB load. :-)

At least the switching regulators seem to be a good choice for
minimizing waste power while running off the solar power.

1N4007s seem to be popular there. :-) I remember that Transitron
used to make what they called "Stabistors" -- silicon diodes
characterized for the forward voltage drop and the temperature
coefficient thereof. They were used in series with zener diodes in
potted regulator blocks to provide stable output voltages with
temperature variations. A lot more efficient than putting the zener in
a crystal oven, which I have seen done many places. (Even some of the
Power Designs power supplies which had switch selectable output voltage
-- for 10-position switches for dialing in volts, tenths, hundredths,
and mV, with a toggle switch to add in an extra 10V, and a pot to adjust
the output in 100s of uV. Lovely little lab supplies -- and quite
accurate, once you allow the crystal oven to stabilize. (It bypasses
the power switch, so if you leave it plugged in, the oven is already
stable when you turn it on.)

Enjoy,
DoN.

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