Diode explanation

[jhabib]

Hey guys, slowly learning this stuff, I have a diode question.  How does letting current flowing in one direction provide for a smaller threshold?

[Cliff Schecht]

The current through a diode is exponentially proportional to the voltage going into the diode as predicted by Shockley's diode equation. This is a temperature dependent term however and varies widely from one diode to the next so it's never a good idea to rely on these parameters being constant. There is a small part in the forward conduction region that can act as a voltage controlled resistor that has a wide dynamic range without needing a lot of control voltage. This resistance varies widely from part to part (min and max) but in general can do a good job of controlling non-critical elements of a circuit.

I hope this answers your questions because I'm not sure which threshold you are talking about .