(SEM V) THEORY EXAMINATION 2020-21 INTEGRATED CIRCUITS

SECTION A (Any 2 Questions Explained Briefly)
 

What is slew rate of an op-amp?
Slew rate is the maximum rate of change of output voltage of an operational amplifier with respect to time. It indicates how fast an op-amp can respond to a rapidly changing input signal and is usually expressed in volts per microsecond (V/µs). A higher slew rate means better performance at high frequencies.
 

Define lock range and capture range of a PLL.
Lock range is the range of input frequencies over which a phase-locked loop can maintain lock once it is achieved. Capture range is the range of frequencies over which the PLL can initially acquire lock. The capture range is always smaller than the lock range.
 

SECTION B (Any 2 Questions Explained)
 

Explain output short-circuit protection in IC 741.
Output short-circuit protection in IC 741 prevents damage when the output is accidentally shorted to ground. This protection is achieved using internal current-limiting transistors in the output stage. These transistors limit the output current to a safe value, ensuring reliable operation and protecting the IC from overheating.
 

Explain the working of a sample and hold circuit.
A sample and hold circuit captures an input analog signal at a specific instant and holds that value for a certain period. It consists of a switch, capacitor, and buffer amplifier. When the switch is closed, the capacitor charges to the input voltage, and when the switch opens, the capacitor holds that voltage. This circuit is widely used in analog-to-digital converters.
 

SECTION C (Any 2 Questions Explained)
 

Explain the operation of a square wave generator using op-amp.
A square wave generator uses an op-amp configured as a comparator with positive feedback. The output switches between positive and negative saturation levels as the capacitor voltage crosses reference levels. This produces a continuous square wave output, commonly used in timing and clock generation circuits.
 

Explain zero crossing detector and voltage comparator.
A zero crossing detector is a type of comparator that switches its output when the input signal crosses zero voltage. A voltage comparator compares two input voltages and changes the output state depending on which input is higher. These circuits are widely used in waveform shaping and signal processing.
 

Most Questions in This PDF Are Related To
 

Most questions in the Integrated Circuits (KEC-501) paper are related to operational amplifier characteristics, IC 741 internal architecture, active filters, oscillators, waveform generators, sample and hold circuits, PLL, IC 555 timer applications, CMOS logic design, and analog signal processing circuits. The paper mainly focuses on analysis and application of linear and digital integrated circuits.