Measurements & Instrumentation

Static characteristics (accuracy, sensitivity, linearity, hysteresis) describe steady readings, while dynamic characteristics (time constant, rise time) describe how fast an instrument follows a changing input.

Bridge circuits measure an unknown impedance by balancing it against known standards so the detector reads null; the balance condition then gives the unknown independent of supply variations.

A transducer converts a physical quantity into an electrical signal: a strain gauge changes resistance with strain (ΔR/R = Gε), an LVDT gives a voltage proportional to displacement, and a thermocouple generates an EMF from a temperature difference.

A data-acquisition system samples analog signals fast enough to avoid aliasing (f_s ≥ 2f_max) and digitises them with an n-bit ADC whose resolution is full-scale/2ⁿ and quantisation error is ±½ LSB.

Calibration compares an instrument against a traceable standard to correct systematic errors, while error analysis quantifies random scatter and propagates individual uncertainties into a combined uncertainty.