Roy Lewallen wrote:

[...]

The second is that the ratio of reverse to forward current increases as
the signal gets smaller and smaller, reaching one at the limit. This can
be observed by looking at the I-V curve of a diode. At the origin, the
curve is a straight line - the diode behaves just like a resistor.

[...]

Roy Lewallen, W7EL

Excellent description - thanks.

Only one small problem - as Win pointed out, Bob Pease feels a
diode-connected 2N3904 has lower leakage at low voltage than a 1N4148:

"What's All This Comparator Stuff, Anyhow?"

http://www.elecdesign.com/Articles/A...9517/9517.html

Does this mean a 2N3904 has a shallower slope than a 1N4148 through zero, or
perhaps one or the other has an offset, such as the Agilent Zero Bias
Schottky Detector Diodes shown in AN969?

http://www.spelektroniikka.fi/kuvat/schot8.pdf

Regards,

Mike Monett