25, Which of the following statement is correct for the basic transistor =
(A) CB configuration has low input impedance and a low current gain
(B) CC configuration has low output impedance and a high voltage gain
(C) CE configuration has very poor voltage gain but very high input impedance
(D) The current gain of CB configuration is higher than the current gain of
CC configuration

26. A Bipolar Junction transistor is said to be operating in saturation region if
(A) Emitter junction is forward biased and collector junction is reverse biased
(B) Emitter junction is reverse biased and collector junction is forward biased
(C) Both the junctions are forward biased
(D) Both the junctions are reverse biased

27. Pinch — off voltage of a JFET is:
(A) The gate-to-source voltage at which the drain current starts to saturate
(B) The drain-to-source voltage at which the drain current becomes zero
(C) The channel-to-gate voltage at which the drain current becomes zero
(0) The channel-to-gate reverse bias voltage at which the drain current starts to
saturate

28. The best material for the gate region construction of a MOSFET is:
(A) High purity silicon (B) High purity silica
(C) Epitaxial grown silicon (D) Heavily doped polycrystalline silicon

29. The common-emitter short circuit current gain # of a BIT :
(4) Is a monotonically increasing function of J,
(B) Is a monotonically decreasing function of 1,
(C) Increases with /, for low values of J,, reaches a maximum and then decreases
with further increase in J,
(D) Is not a function of J,

30. For full-wave rectification, a four-diode bridge rectifier is claimed to have the following
advantages over a two-diode circuit :

(1) Less expensive transformer
(2) Smaller size transformer and
(3) Suitability for higher voltage application

Of these
(A) Only (1) and (2) are true (B) Only (1) and (3) are true
(©) Only (2) and (3) are true (D) (1), (2) and (3) are true

81. A 1 MHz sinusoidal carrier wave is amplitude modulated by a sine wave of period 100 ws.
Which of the following frequencies will not be present in the modulated output signal?
(A) 990 KHz (B) 1000 KHz
(0) 1010 KHz @)~ 1020 KHz

005/2016 6 A