Obtain symbolic expression for the input resistance of the circuits shown in Figure 5. Let VA=infinity in both circuits. Solution For circuit (2) we have, by applying kirchoffs law V EE -I E R B -V BE =0. V EE -V BE /R B =I B. V EE -I C R E -V CE =0 Solving and simplifying these equations we can find the expression for resistance. a) Vcc=icRc-Vce1-Vce1-Vce2=0 solve this we can find the resistance. .

1. Obtain symbolic expression for the input resistance of the circuits shown in Figure 5. Let
VA=infinity in both circuits.
Solution
For circuit (2) we have,
by applying kirchoffs law
V EE -I E R B -V BE =0.
V EE -V BE /R B =I B.
V EE -I C R E -V CE =0
Solving and simplifying these equations we can find the expression for resistance.
a) Vcc=icRc-Vce1-Vce1-Vce2=0
solve this we can find the resistance.