1. What is the need for an instrumentation amplifier?
In a number of industrial and consumer applications, the measurement of physical quantities
is usually
done with the help of transducers. The output of transducer has to be amplified So that it can
drive the
indicator or display system. This function is performed by an instrumentation amplifier.
2. State the characteristics of an instrumentation amplifier.
The characteristics of an instrumentation amplifier are:
a. High gain accuracy
b. High CMRR
c. High gain stability with low temperature co-efficient
d. Low dc offset
e. Low output impedance
f. High input impedance
3. Draw and write the equation for of an integrator using an op-amp.
4. What is a comparator? List the applications of comparator.
A comparator is a circuit which compares a signal voltage applied at one input of an op-amp
with a known reference voltage at the other input. It is an open loop op - amp with only two
possible outputs
+ Vsat and –Vsat
Zero crossing detectors
Window detector
Time marker generator
Phase meter
Digital interfacing
Schmitt trigger
Oscillators
5. What is a Schmitt trigger or regenerative comparator?
Schmitt trigger is a regenerative comparator. It converts any irregular shaped input into a
square waveoutput. The output of Schmitt trigger swings between upper and lower threshold
voltages, which are the reference voltages of the input waveform. The input voltage Vin >
VuT, output V0 goes to -Vsat and Vin < VLT
, V0 is at +Vsat and the result is a square wave output.
Give an application for each of the following circuits.
a. Voltage follower: It has high input impedance and low output impedance. So it is used to
eliminate loading effect. Also used as a buffer.
b. Peak detector: Used in amplitude modulation as detector and in test and measurement
instrument applications
c. Schmitt trigger: Used in wave shaping circuit to convert any input to square wave output
and acts as square wave converter.
d. Clamper: It is used to add dc signal to the ac output both in positive and negative sides.
Often it is used in Television.(TV)
6. Draw the pin diagram of AD633
7. What are advantages of emitter coupled transistor pair?
The advantages of emitter coupled transistor pair are,
High current gain
More stability
Compact and easily implemented in IC
8. What is analog multiplier? Name a few applications of an analog multiplier.
Applications of analog multiplier are:
Frequency doubling.
Frequency shifting.
Phase angle detection.
Squaring.
Multiplication.
Division.
Waveform generation.
9. What is analog multiplier?
A multiplier produces an output V0, which is proportional to the product of two inputs v x and
vy.V0= kvxvy
10. Define the three stages through which PLL operates?
Lock-in range or tracking range:
The range of frequencies over which the PLL can maintain lock with the incoming signal is
called the lock-in range or tracking range.
It is expressed as a percentage of the VCO free running frequency.
Capture range:
The range of frequencies over which the PLL can acquire lock with an input signal is called
the capture range.
It is expressed as a percentage of the VCO free running frequency
Free running mode:
Free running mode is an interactive computer mode that allows more than one user to have
Simultaneous use of a program.
