Tutorial Sheet 2

THAPAR INSTITUTE OF ENGINEERING &TECHNOLOGY

(Deemed to be University)

Department of Electronics and Communication Engineering

Tutorial Sheet-2 (Electronics Engineering, UEC-001)

1) Do the following -

a) Determine the thermal voltage of a semiconductor at a temperature of 20°C.

b) For the same diode of part (a), find the diode current if Is = 40 nA,h= 2 (ideality factor),

and the applied bias voltage is 0.5 V.

2) In the reverse-bias region the saturation current of a silicon diode is about 0.1 mA (T = 20°C).

Determine its value if the temperature is increased by 40°C.

3) Determine the DC resistance level for the diode at

a) I_D =1 mA (low level) and V_D = 0.25 V

b) I_D =5 mA (high level) and V_D = 0.6 V

c) I_D=0 and V_D=0.1V

d) V_D = -8 V (reverse biased) and I_S = -1 μA. Also plot the V-I characteristic curve for this diode and state whether the diode is Si based or Ge.

4) Determine the AC resistance of diode at

a) I_D = 2 mA, when a swing of 2 mA above and below the specified current is chosen

corresponding to the voltage V_D change from 0.76 V to 0.65 V.

b) I_D = 25 mA, when a swing of 5 mA above and below the specified current is chosen

corresponding to the voltage V_D change from 0.8 V to 0.78 V.