How do you identify if the Diode is made of si or ge?

Question

How do you identify if the Diode is made of si or ge?

Answer 1

Not entirely easy. A typical germanium diode will have a lower forward voltage drop than a typical silicon diode. Germanium should be about 0.3V compared to silicon's 0.5-0.6V. There are silicon types with low Vf though, Schottky diodes for example - these are generally limited to low current types. Higher power germanium diodes (50A+) may have a higher Vf as well, although you aren't likely to come across these.

Of course, if your part has a number on it you should look it up and find out exactly what it is...