# Questions & Answers of Operational Amplifiers: Characteristics and Applications

## Weightage of Operational Amplifiers: Characteristics and Applications

Total 32 Questions have been asked from Operational Amplifiers: Characteristics and Applications topic of Analog and Digital Electronics subject in previous GATE papers. Average marks 1.56.

The op-amp shown in the figure is ideal. The input impedance $\style{font-family:'Times New Roman'}{\frac{v_{in}}{i_{in}}}$ is given by

The approximate transfer characteristic for the circuit shown below with an ideal operational amplifier and diode will be

For the circuit shown below, assume that the OPAMP is ideal.

Which one of the following is TRUE?

The circuit shown below is an example of a

For the circuit shown below, taking the opamp as ideal, the output voltage Vout in terms of the input voltages V1 , V2 and V3 is

Of the four characteristic given below, which are the major requirements for an instrumentation amplifier?
P. High common mode rejection ratio
Q. High input impedance
R. High linearity
S. High output impedance

Consider the circuit shown in the figure,. In this circuit R = 1 k$\mathrm{\Omega }$, and C=1 $\mathrm{\mu }$F. The input voltage is sinusoidal with a frequency of 50 Hz, represented as phasor with magnitude ${V}_{\mathit{i}}$ and phase angle 0 radian as shown in the figure. The output voltage is represented as a phasor with magnitude ${V}_{0}$ and phase angle δ radian. What is the value of the output phase angle δ (in radian) relative to the phase angle of the input voltage?

The op-amp shown in the figure has a finite gain A = 1000 and an infinite input resistance. A step-voltage ${V}_{i}$= 1 mV is applied at the input at time t = 0 as shown. Assuming that the operational amplifier is not saturated, the time constant (in millisecond) of the output voltage ${V}_{0}$ is

The operational amplifier shown in the figure is ideal. The input voltage (in Volt) is . The amplitude of the output voltage ${V}_{0}$ (in Volt) is ________.

In the following circuit, the transistor is in active mode and $V_C=2\;V$. To get $V_C=4\;V$, we replace ${R}_{c}$ with $R'_C$ . Then the ratio $R'_C/R_C$ is _________.

The filters F1 and F2 having characteristics as shown in Figures (a) and (b) are connected as shown in Figure (c).

The cut-off frequencies of F1 and F2 are ${f}_{1}$ and ${f}_{2}$ respectively. If ${f}_{1}$< ${f}_{2}$, the resultant circuit exhibits the characteristics of a

The saturation voltage of the ideal op-amp shown below is ±10 V. The output voltage ${v}_{0}$ of the following circuit in the steady-state is

Given that the op-amps in the figure are ideal, the output voltage V0 is

In the figure shown, assume the op-amp to be ideal. Which of the alternatives gives the correct Bode plots for the transfer function $\frac{{V}_{0}\left(\omega \right)}{{V}_{i}\left(\omega \right)}$ ?

An operational-amplifier circuit is shown in the figure.

The output of the circuit for a given input vi is

The transfer characteristic of the Op-amp circuit shown in figure is

In the circuit shown below what is the output voltage (Vout) in Volts if a silicon transistor Q and an ideal op-amp are used?

In the circuit shown below the op-amps are ideal. Then Vout in Volts is

The circuit shown is a

A low – pass filter with a cut-off frequency of 30Hz is cascaded with a high-pass filter with a cut-off frequency of 20Hz. The resultant system of filters will function as

for the circuit shown below

The CORRECT transfer characteristic is

Given that the op-amp is ideal, the output voltage V0 is

The nature of feedback in the opamp circuit shown is

The following circuit has R = 10kΩ, C = 10µF The input voltage is a sinusoid at 50Hz with an rms value of 10V. Under ideal conditions, the current iS from the source is

Transformer and emitter follower can both be used for impedance matching at the output of an audio amplifier. The basic relationship between the input power Pin and output power Pout in both the cases is

An ideal opamp circuit and its input waveform are shown in the figures. The output waveform of this circuit will be

The block diagrams of two types of half wave rectifiers are shown in the figure. The transfer characteristics of the rectifiers are also shown within the block.

It is desired to make full wave rectifier using above two half-wave rectifiers. The resultant circuit will be

 (A) (B) (C) (D)

A waveform generator circuit using OPAMPs is shown in the figure. It produces a triangular wave at point ‘P’ with a peak to peak voltage of 5 V for Vi = 0 V.

If the voltage Vi is made +2.5 V, the voltage waveform at point ‘P’ will become

 (A) (B) (C) (D)

A general filter circuit is shown in the figure:

If R1 = R2 = RA and R3 = R4 = RB, the circuit acts as a

A general filter circuit is shown in the figure:

The output of the filter in Q.80 is given to the circuit shown in figure :
The gain v/s frequency characteristic of the output (vo) will be

 (A) (B) (C) (D)