The figure below shows a three-stage amplifier in which the stages are directly coupled. The amplifier, however, utilizes bypass capacitors and as such its frequency response falls off at low frequencies. For our purpose here, we shall assume that the capacitors are large enough to act as perfect short circuits at all signal frequencies of interest.
a. Find the dc bias current in each of the three transistors. Also find the dc voltage at the output. Assume|??????|= 0.7 V,ß = 100and neglect Early effect.
b. Find the input impedance and the output resistance. c. Evaluate the voltage gain vo/vi.
4)An NMOS transistor that is operated with a small vDSis found to exhibit a resistance rDS. By what factor will rDSchange in each of the following situations?
(a) VOVis doubled.
(b) The device is replaced with another fabricated in the same technology but with double
(c) The device is replaced with another fabricated in the same technology but with both
the width and length doubled.