Input Potential
Electrical potential applied to a transducer or resistive bridge to enable the conversion of a physical quantity into a measurable signal. The magnitude of excitation voltage determines the sensitivity of the output, where a higher input generally yields a larger millivolt signal for a given load. Stability of this source is required for high-resolution data acquisition.
Thermal Impact
Power dissipated as heat within a strain gauge or pressure sensor is proportional to the square of the applied excitation voltage. Excessive heating causes bridge imbalance and introduces measurement drift that masks the actual physical change. Precision circuits often use 2.5V or 5V levels to maintain a balance between signal-to-noise ratio and thermal stability.
Constant current supplies are an alternative for environments where lead wire resistance fluctuates due to external temperature changes.
Bridge Sensitivity
Bridge-based sensors produce an output that is a direct ratio of the input supply. When the excitation voltage fluctuates by even a small percentage, the resulting data contains errors that can be mistaken for mechanical load changes. Regulated power supplies or ratiometric measurement techniques compensate for these variances in the signal chain.
Instrument Calibration
Precision voltmeters verify the accuracy of the supply specifically at the sensor terminals to account for lead wire losses. This practice prevents the degradation of the calibration factor of the system. Verification occurs during initial setup and at periodic intervals to maintain the integrity of the sensing loop.
