Amplifiers » Exercise – 1
1. The important characteristic of emitter-follower is :
(a) high input impedance and high output impedance
(b) high input impedance and low output impedance
(c) low input impedance and low output impedance
(d) low input impedance and high output impedance
2. Most of linear ICs are based on the two transistor differential amplifier because of its :
(a) input voltage dependent linear transfer characteristic
(b) high voltage gain
(c) high input resistance
(d) high CMRR
3. The maximum possible collector circuit efficiency of an ideal class A power amplifier is :
(a) 15%
(b) 25%
(c) 50%
(d) 75%
4. If the feedback signal is returned to the input in series with the applied voltage, the input impedance :
(a) decreases
(b) increases
(c) does not change
(d) becomes infinity
5. In an amplifier with negative feedback, the bandwidth is :
where A = gain of the basic amplifier and β = feedback factor
(a) increased by a factor of β
(b) decreased by a factor of β
(c) increased by a factor of (1+Aβ)
(d) not affected at all by the feedback
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