# Feedback Amplifiers

 Question 1
A good transimpedance amplifier has
 A low input impedance and high output impedance. B high input impedance and high output impedance. C high input impedance and low output impedance. D low input impedance and low output impedance.
GATE EC 2018   Analog Circuits
Question 1 Explanation:
A good transimpedance amplifier should have low input impedance and low output impedance
 Question 2
A good transconductance amplifier should have
 A high input resistance and low output resistance B low input resistance and high output resistance C high input and output resistances D low input and output resistance
GATE EC 2017-SET-1   Analog Circuits
Question 2 Explanation:
A good transconductance amplifier should have very high input resistance and very high output resistance.
 Question 3
The desirable characteristics of a transconductance amplifier are
 A high input resistance and high output resistance B high input resistance and low output resistance C low input resistance and high output resistance D low input resistance and low output resistance
GATE EC 2014-SET-3   Analog Circuits
 Question 4
The feedback topology in the amplifier circuit ( the base bias circuit is not shown for simplicity) in the figure is
 A Voltage shunt feedback B Current series feedback C Current shunt feedback D Voltage series feedback
GATE EC 2014-SET-2   Analog Circuits
Question 4 Explanation:
The feedback topology in the amplifier circuit is
current series because
Sampling $\rightarrow$ Current
Mixing $\rightarrow$ Series
So current-series feedback
 Question 5
In the ac equivalent circuit shown in the figure, if $i_{in}$ is the input current and $R_{F}$ is very larger, the type of feedback is
 A voltage-voltage feedback B voltage-current feedback C current-voltage feedback D current-current feedback
GATE EC 2014-SET-1   Analog Circuits
Question 5 Explanation:
Sampling $\rightarrow$ current
Mixing $\rightarrow$ voltage
 Question 6
In a voltage-voltage feedback as shown below, which one of the following statements is TRUE if the gain k is increased?
 A The input impedance increases and output impedance decreases. B The input impedance increases and output impedance also increases. C The input impedance decreases and output impedance also decreases. D The input impedance decreases and output impedance increases.
GATE EC 2013   Analog Circuits
Question 6 Explanation:
The given configuration is a voltage-series feedback configuration.
So, the input impedance increases
$R_{i f}=R_{i}\left(1+A_{0} K\right)$
and, the output impedance decreases
$R_{o f}=\frac{R_{o}}{1+A_{o} K}$
 Question 7
In a transconductance amplifier, it is desirable to have
 A a lage input resistance and a large output resistance B a large input resistance and a small output resistance C a small input resistance and a large output resistance D a small input resistance and a small output resistance
GATE EC 2007   Analog Circuits
 Question 8
The input impedance ($Z_{i}$) and the output impedance ($Z_{0}$) of an ideal transconductance (voltage controlled current source) amplifier are
 A $Z_{i}=0,Z_{0}=0$ B $Z_{i}=0,Z_{0}=\infty$ C $Z_{i}=\infty ,Z_{0}=0$ D $Z_{i}=\infty ,Z_{0}=\infty$
GATE EC 2006   Analog Circuits
 Question 9
The effect of current shunt feedback in an amplifier is to
 A increase the input resistance and decrease the output resistance B increases both input and output resistance C decrease both input and output resistance D decrease the input resistance and increase the output resistance
GATE EC 2005   Analog Circuits
 Question 10
Voltage series feedback (also called series-shunt feedback) results in
 A increase in both input and output impedances B decrease in both input and output impedances C increase in input impedance and decrease in output impedance D decrease in input impedance and increase in output impedance
GATE EC 2004   Analog Circuits
There are 10 questions to complete.