Natural Oscillation
Inductive and capacitive reactances balance each other at a specific frequency where the electrical system oscillates with minimal energy input. Calculating the resonant frequency determines the primary operating point of many inductive and capacitive sensing systems. This frequency is determined by the active and parasitic electrical components in the circuit.
Peak Response
Signal amplitude reaches its maximum value when the sensor is excited at its natural frequency. This behavior is used to maximize the sensitivity of the measurement system to small physical changes. The sharpness of this peak is defined by the quality factor of the resonant circuit.
Circuit Influence
Connecting cables and input amplifier stages add parasitic capacitance that shifts the oscillation point away from the sensor design value. This capacitive loading must be factored into the initial system design to prevent the circuit from operating outside its intended frequency range. High-precision instruments utilize active shielding techniques on the cables to isolate the sensor from these external capacitive effects.
Circuit designers verify these parameters during final assembly to ensure stability.
System Drift
Temperature variations modify the physical dimensions of the sensor coil and substrate, which shifts the natural oscillation point over time. Compensation algorithms or temperature-stable dielectric materials are used to mitigate this drift. Tracking these shifts is necessary to maintain measurement accuracy.
