"Winfield Hill" -edu wrote in
message ...
john jardine wrote...

I know where you're coming in from, but whichever way I look at Win's
graphs
I'm seeing a straight line for that 1N4148 at 0-30mv levels. Yes, the
scales
are log-log but the constant of proportionality is dead straight linear.
I.e
1mv RF in gives 1e-10 amps and 10mV in gives 1e-9 amps and pro-rata for
all
points in between (you did see the double decade increments?). This
agrees
with the 10Mohm value that's marked on the graph.

Right, but that part of my measurements cries out for further bench
exploration. It represents only one part, and is unconfirmed. Also,
what happens if the voltage is reversed? Are we to believe the diode
is a 10M resistor, shunted by a diode? I'm not comfortable with that.


--
Thanks,
- Win

Test on a 1N4148.
ForwardV DiodeR
+50mV 8megs.
+30mV 9megs.
+20mV 10megs.
+10mv 12megs.
+5mV 21megs.
ReverseV
-5mV 21megs.
-10mV 30megs.
-30mV 270megs.

All the figures are suspect as the noise filter had a long settling time
and I was too lazy to wait but they do show a very sharp reverse cutoff, at
about 10-15mV.

And a bonus, a rectification test feeding the diode from a 60Hz source and
10k series R ...
ACi/p DCo/p
430mV 59mV
300mV 12mV
200mV 2.4mV
100mV 140uV
60mV 66uV
30mV 18uV
20mV 9uV
10mV 1uV
regards
john