germanium diodes suspect at 0.96vF

[EATyourGuitar]

I got some new in the box sylvania germanium diodes with 4 different color bands. it goes black red orange yellow or something similar. the package is the size of a 1N270 or 1N34 and the junction looks the same. they have a range from 0.68vF to 0.96vF. I am quite perplexed how to proceed in testing them. even if they are germanium, they might have the right curve but too much headroom for what I want to do with them. there is the advantage of switching between germanium and silicon diodes with no change in volume. this is a welcome change from the traditional germanium diode.

real or fake?

[PRR]

Put a 9V batt, a 10K resistor, and the diode in series.

This puts near 1mA in the diode, a convenient and *known* current. (I never know what these smart-testers are testing at.)

Measure the voltage across the diode.

If it is 9V, turn the diode around.

Also test known-recipe diodes, 1N4148 or 1N4007. Or any two pins of a transistor.

You really expect Ge to be 0.2V-0.3V, Si 0.6V-0.7V.

By electro/hydraulic theory, if two similar-size devices show the same voltage at the same reasonable current, they will have nearly identical "curves" for a long way either side of that point.

There WERE "point contact" Si devices, and some would read in the 0.75V range at a mA or so. Early 1N914, fer example. (Modern 1N914 are 1N4148 marked to match the order.)

Or stick em in, use your ears.