[sdiy] Low leakage diodes

[harrybissell]

Howdy all...

well its confirmed... the culprits were the 1N4148 diodes which were
leaky...

not out of their spec, just not very good at .025uA.

I tried the FDH333 low leakage diodes, which at .001uA were MUCH
better.

Also tried the base-collector junction of the 2N3904, which worked as
well as the FDH333.

I didn't try the FET because I don't have any, and think they would be
too expensive for what I need...

I also tried "darkness" and painting the 1N4148 with a black marker...
it made no discernable difference...

This is the first time I've seen diode leakage, because my previous
designs
included the diodes in a feedback loop which kept the voltage at andoe
and
cathode just about equal.... so no leakage was noticible.

Live and learn. Thanks to all the tipsters on this one

H^) harry