Pressure transducers and resistance behavior: evaluate the statement—“A pressure transducer is a device whose resistance changes inversely in proportion to applied pressure.” Choose the most accurate assessment.

Introduction / Context:
Pressure transducers convert pressure into an electrical signal. Many common industrial sensors use strain-gauge Wheatstone bridges, capacitive diaphragms, piezoresistive elements, or piezoelectric crystals. The question tests understanding of whether “inverse proportional resistance change” is a general defining behavior of pressure transducers.

Given Data / Assumptions:

• Typical pressure transducer types: strain-gauge (piezoresistive), capacitive, piezoelectric.
• “Inversely proportional” means R ∝ 1/P strictly.
• We assess generality across technologies rather than a single special case.

Concept / Approach:
In a strain-gauge pressure sensor, pressure deflects a diaphragm, producing tensile or compressive strain in gauges. The gauge resistance follows R = R0 * (1 + GF * ε), with ε proportional to strain, which in turn depends on pressure via the diaphragm mechanics. This is not universally “inverse”; the sign and linearity depend on gauge orientation and mechanical design. Capacitive sensors vary capacitance C with diaphragm spacing; the readout circuitry typically converts C changes to voltage, not relying on an inverse resistance law. Piezoelectric sensors generate charge proportional to dynamic pressure changes, again not an inverse resistance relation.

Step-by-Step Solution:

Verification / Alternative check:
Examine datasheets: bridge output is specified in mV/V full-scale per pressure, not as R inversely proportional to P. Calibration curves show near-linear bridge output with pressure over range, not a 1/P law.

Why Other Options Are Wrong:
“Correct only for piezoelectric” and “Correct only for capacitive” are inaccurate because those technologies do not encode pressure as inverse resistance. “Correct for all strain-gauge bridges” is false; gauge orientation can increase or decrease R with applied pressure and does not yield a strict 1/P relationship.

Common Pitfalls:
Assuming all sensors change resistance in the same simple way; conflating inverse proportionality with “opposite direction.”

Final Answer:
Incorrect