Answer:
Step-by-step explanation:
The forward-biased voltage drop of a semiconductor diode depends on the material it is made of and the method of fabricating the junction.
Voltage drops
A silicon diode will have a voltage drop that can be estimated as 0.7 V. The actual value will depend on current and temperature.
A germanium diode will have a voltage drop closer to 0.3 V, again depending on current and temperature.
A Schottky diode may have a voltage drop between 0.2 and 0.3 V, so may be difficult to distinguish from a germanium diode.
If it measures 0.3 V, the diode is probably made of germanium, and is forward biased.
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The reverse-biased voltage reading will generally match the open-circuit voltage of the testing device.