our Professor asked me to prove the equation of dynamic resistance of diode , he want me to explain him where did the equation come from !


the equation is this : [r]_{}[/AC]=[n.[V]_{}[/T]]/[/_{}[/Q]]

r is for resistance
[V]_{}[/T] stands for thermal voltage
_{}[/Q] is the I at operating point of diode

so if you know how it has made , please let your friend knows it too

 

It's hard to follow your notation. How about making it a bit easier for those whom you are asking for free assistance and format your equations using tex. There's a sticky at the top of the Homework Help forum that tells you how.

 

Here's a hint: Dynamic resistance is dV/dI (change in voltage divided by change in current).
Do you know the diode equation?