LED Curve Tracing / FV knee with DCA75

[chromesphere]

I tested the diode again this morning with the quick test function of the DCA, it showed a FV of .63v which is suspicious of course being a germanium diode.

It's not suspicious, it's something about the Peak. Fv is also current-dependent, but despite my interest in diodes I lack the knowledge to explain real testing methods. 

Agreed Jon!  Depends on the test current. A comment I wrote in a later post on this thread which is in line with what you said:

"EDIT: An example is the BAT41.  The peaks quick measurement shows .629v at 5ma.  My bk dmm shows 0.389v (at approx 1.2ma).  Take a look at the curve trace of the bat41, you can see these 2 corresponding measurements. "

[EBRAddict]

I tried a different test on some of the diodes, measuring the resistance each way with a multimeter. Interesting results:



The C-A test was done with the meter + lead on the cathode and the - lead on the anode and vice versa for the A-C test.



As suspected the 1N34A were leaky.

I ran a second test, let's put the Si - Ge in series and test the clipping. If reverse leakage is the issue the Si diode should stop it. And...



Still no good clipping