Alternating Opposition
Alternating current opposition is defined by the ratio of voltage to current in a circuit where phase differences exist. Sensing circuits rely on complex impedance to capture both resistive losses and reactive energy storage across different operating conditions. This vector quantity resolves the magnitude and phase of the electrical response.
Phase Relationship
Phase angles determine the transition between resistive and capacitive or inductive behaviour in a sensor coil. A phase shift occurs when the voltage across a sensing element leads or lags the excitation current. This shift reveals the presence of conductive or magnetic materials near the sensor.
Measurement Vector
Demodulation techniques extract the real and imaginary parts of the electrical response as separate signals. These components are plotted as resistance and reactance to monitor material properties. Temperature changes or cable lengths can introduce offsets that require compensation during calibration.
When a metal target approaches the sensor, the eddy currents alter the inductance, which shifts the measured vector in a predictable path. A reference calibration standard is used to map these changes to physical distance or material thickness.
Frequency Variation
Operating frequencies modify the relative influence of the reactive part of the electrical response. At low frequencies, resistive components tend to dominate the measurements. High frequencies increase the contribution of inductive reactance, which alters the overall signal path.
