What does 0.7V silicon or 0.3V germanium diode mean?

[amaresh92]

i wonder if anyone can tell me the meaning of the statement " a 0.7V silicon diode or 0.3V germinium diode"?
is this given voltage(0.7 or 0.3) specify the voltage drop across the diode when it is forward biased?

advanced thanks.

 

[dlgoff]

is this given voltage(0.7 or 0.3) specify the voltage drop across the diode when it is forward biased?

Yes. Note that for germanium diodes, the forward bias voltage is said to be around 0.2 to 0.3 volts and for silicon diodes around 0.6 to 0.7 volts.

 

[granpa]

its probably easiest to understand in led's

http://docs.google.com/viewer?a=v&q...rRfKMb&sig=AHIEtbRfb5GKJfTHllpd8OJj5E1BFBUZRg

http://en.wikipedia.org/wiki/Light-emitting_diode#Physics
http://en.wikipedia.org/wiki/Light-emitting_diode#Colors_and_materials

 

[Chad Stoltzma]

Another easy way to look at it is, it's the small amount of voltage needed to turn on the switch. The Si, Ge, GaAs...whatever type, is just the material used during the fabrication process which has different electrical properties.