The current-voltage characteristic of an ideal p-n junction diode is given by
`i=i_0(e^eV//kT-1)`
where the drift current `i_0`equals `10(mu)A`.Take the temperature T to be 300K.(a)Find the voltage `v_0`for which `e^(eV//kT)=100`.One can neglect the term 1 for vlatages greater than this value (b)Find an expression of the dynamic resistance of the diode as a function of V for `VgtV_0`.(c)Find the voltage for which the dynamic resistance is `2.0 (Omega)`

Explanation

(a) Given that
`i = i_0(e^(eV//KT-1))`
`i ~~ i_0e^(e(V//KT))`
Again that e^(e(V//KT)) = 100`
`rArr (eV)/(kT) = In 100`
`V = (In 100xxkT)/(e)`
` = (2xx8.62xx10^(-5)eVxx300k)/(ek)`
`= 0.51V`
(b) Given that
`i = i_0(e^(eV//kT)-1)`
Different w.r.t.'q'
`(di)/(dV) = i_0 (e)/(kT). e^(eV//kT)`
`rArr (1)/(R) = (ei_0)/(kT) e^(eV//kT)`
`rArr R = (kT)/(ei_0) e^(V//kT)`
(c) Using`R = 2Omega` in above exeperssion
`2 = (8.62xx10^(-5)xx eVxx300k)/(ek) e^(-eV//8.62xx300k)`
rArr V = 0.25V`