(SEM V) THEORY EXAMINATION 2022-23 SENSORS, ACTUATORS AND SIGNAL PROCESSING

SECTION A (2 × 10 = 20 Marks)

Attempt all questions in brief
 

(a) Environmental parameters of sensors
Environmental parameters measured by sensors include temperature, pressure, humidity, light intensity, vibration, gas concentration, and radiation. These parameters help in monitoring environmental conditions and system performance in industrial and engineering applications.
 

(b) Characteristics of transducers
Transducers are devices that convert one form of energy into another. Important characteristics include sensitivity, accuracy, linearity, repeatability, resolution, and response time. These characteristics determine the performance and reliability of the transducer.
 

(c) Working of thermal sensor
A thermal sensor works on the principle that temperature changes cause a variation in physical properties such as resistance or voltage. This variation is converted into an electrical signal, which is measured to determine temperature.
 

(d) Use of flow meter in sensors
A flow meter is used to measure the rate of fluid flow in pipes or channels. It helps monitor liquid or gas flow in industrial processes, water supply systems, and chemical plants.
 

(e) Basic characteristics of radiation sensor
Radiation sensors detect and measure ionizing or non-ionizing radiation. Important characteristics include sensitivity, energy range, accuracy, and response time. They are used in safety monitoring and medical applications.
 

(f) Use of filters in sensors
Filters are used to remove noise and unwanted frequency components from sensor signals. They improve signal clarity and accuracy by allowing only desired frequencies to pass.
 

(g) Types of motion in actuation systems
Actuation systems produce different types of motion such as linear motion, rotary motion, and oscillatory motion. These motions are used depending on the application requirements.
 

(h) Working of mechanical switches
Mechanical switches work by physically opening or closing electrical contacts. When the switch is pressed, the contacts touch and allow current flow; when released, the circuit opens.
 

(i) Signal defined in terms of waves
A signal can be defined as a time-varying quantity represented by waves. These waves are characterized by amplitude, frequency, wavelength, and phase.
 

(j) Features of Digital Signal Processor (DSP)
DSPs are specialized processors designed for fast numerical operations. They support real-time processing, parallel execution, low power consumption, and efficient handling of digital signals.
 

SECTION B (10 × 3 = 30 Marks)
 

(a) Sensitivity and linearity of sensors
Sensitivity refers to the ability of a sensor to detect small changes in input. Linearity indicates how closely the sensor output follows a straight-line relationship with input. High sensitivity and good linearity are essential for accurate measurements.
 

(b) Hall effect and its relation to sensors
The Hall effect occurs when a magnetic field is applied perpendicular to current flow in a conductor, producing a voltage. Hall effect sensors use this principle to detect magnetic fields, position, and speed.
 

(c) Standard hydrogen electrode working principle
The standard hydrogen electrode is used as a reference electrode in electrochemical measurements. It operates based on hydrogen ion concentration and provides a stable reference potential.
 

(d) Working principle of DC motor
A DC motor works on the principle that a current-carrying conductor placed in a magnetic field experiences a force. This force causes rotation of the motor shaft, converting electrical energy into mechanical energy.
 

(e) Nyquist rate and sampling techniques
The Nyquist rate is the minimum sampling rate required to avoid aliasing and is equal to twice the highest signal frequency. Sampling techniques include uniform sampling, non-uniform sampling, and oversampling.
 

SECTION C
 

Q3 (a) Inductive sensors

Inductive sensors operate based on changes in inductance caused by nearby metallic objects. They are commonly used for proximity detection, position sensing, and speed measurement in industrial automation.
 

Q4 (b) Resistance change type thermometric sensors

These sensors work on the principle that electrical resistance of materials changes with temperature. Examples include RTDs and thermistors, which are widely used for accurate temperature measurement.
 

Q5 (b) Smart sensors and interface standards

Smart sensors integrate sensing elements with signal processing and communication capabilities. Interface standards such as I²C, SPI, and IEEE 1451 ensure compatibility and reliable data transfer.
 

Q6 (b) Pneumatic and hydraulic actuation systems

Pneumatic systems use compressed air to produce motion, while hydraulic systems use pressurized fluids. Pneumatic systems are faster and cleaner, whereas hydraulic systems provide higher force output.
 

Q7 (b) Classification of signal processing systems

Signal processing systems are classified as analog and digital systems. Analog systems process continuous signals, while digital systems process discrete signals using algorithms and processors.