JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV SENSORS AND TRANSDUCERS Previous Question Paper (September - 2020 - R16)

Transducers are classified based on the following criteria:

• Based on transduction principle: Resistive, capacitive, inductive, piezoelectric, photoelectric, and electrochemical transducers.
• Based on output signal: Analog transducers (continuous output) and digital transducers (discrete or pulse output).
• Based on power source: Active transducers (self-generating, e.g., thermocouples) and passive transducers (require external power, e.g., LVDT).
• Based on application: Primary transducers (sensing element) and secondary transducers (signal conditioning).

The basic requirements of a transducer include:

• Linearity: The output should be directly proportional to the input over the entire operating range.
• Sensitivity: The ability to produce a measurable output change for a small input change.
• Stability: The transducer must maintain its performance characteristics over time and under varying environmental conditions.
• Dynamic Response: The ability to track rapid changes in the input signal without significant lag or distortion.
• Ruggedness: Capability to withstand mechanical vibrations, shock, and environmental stress.
• High Signal-to-Noise Ratio: Minimizing interference to ensure accurate signal transmission.

Accuracy refers to the closeness of a measured value to the true or accepted standard value. It indicates the degree of correctness of the measurement and is often expressed as a percentage of the full-scale reading.

Precision refers to the consistency or repeatability of a set of measurements. It describes the ability of an instrument to yield the same output for repeated applications of the same input, regardless of how close that value is to the true value.

In summary, accuracy relates to the error relative to the truth, while precision relates to the spread or dispersion of repeated measurements.