1. In the cascade amplifier circuit shown, determine the values
of R1, R2 and RL such that the quiescent current through the
transistors is 1 mA and the collector voltages are VC1 = 3 volts,
and VC2 = 6 volts. Take VBE = 0.7 volts and assume β of the
transistors is high and base currents to be negligible.
2. Given an NMOS circuit as shown. The specifications of the
circuit are :
VDD = 10 volts, β = µnCox(W/L) = 10-4 Amp/V2,
VT = 1 volt, and IDS = 0.5 mA.
Evaluate VDS and RD. Neglect body effect.
3. Find static noise margins for a BJT inverter shown in figure.
Transistor used is an npn type with specifications as follows.
4. For a typical n-p-n transistor, the following data are available :
(a) WC = 20 µm and collector doping = 5 x 1018/cm3
(b) WE = 1 µm and emitter doping = 10 x 1019/cm3
(c) Base doping = 5 x 1015 /cm3
(d) Minority carrier life time in the Base region is τn = 5 µsec
5. An n-type silicon bar is doped uniformly by phosphorous atoms
to a concentration 4.5 x 1013/cm3.
The bar has cross section of 1 mm2 and length of 10 cm.
It is illuminated uniformly for region x<0 as shown in figure.
Assume optical generation rate 1021 electron-hole pairs per cm3
per second, for this case.
The hole lifetime and electron lifetime are equal to 1µsec.
Evaluate the hole and electron diffusion current s at x = 34.6 µm.