Hi All
please help me out with the following problem.

Temperature of the p-n junction is 300k,saturation current to be 5.0nA and emisssion coefficient to be 1,Calculate the ratio of the current through the diode for a 0.5v forward bias to the current for a 0.5v reverse bias.What is your comment on this ratio.

 

Have you taken a look at the material on diodes in the AAC ebook?

hgmjr

 

I=Is*(e^(Vd/k*VT)-1)

where
I=diode through diode
Is=reverse saturation current
Vd=voltage across diode (actually across the junction)
k=emission coefficient (constant which depends upon the construction of the diode)

VT=thermal voltage =KT/q which at 300K approximately equals 25mV

For Vd=0.5V

I=(0.5*10^-9)*(e^(0.5/1*0.025)-1)=0.243A=243mA

for Vd=-0.5

I=(0.5*10^-9)*(e^(-0.5/1*0.025)-1)=-4.99*10^-10=-0.49nA