An inductive proximity sensor uses the principle of __________ to sense the presence of a metallic object.

An inductive proximity sensor uses the principle of __________ to sense the presence of a metallic object.

• A. Capacitance
• B. Induction
• C. Photoelectric effect
• D. Resonant frequency

Answer: (B)

The sensing principle is electromagnetic induction. An inductive proximity sensor uses a coil driven by an oscillator to emit an alternating magnetic field at the sensing face. When a metallic object comes into range, eddy currents are induced in the metal. These currents create their own magnetic field that opposes the original field, changing the coil’s impedance (and often the oscillator’s frequency or amplitude). The sensor detects this change and switches its output. This approach is specifically suited to metal targets and works without any physical contact. Capacitance-based sensing responds to changes in dielectric properties, photoelectric sensing relies on light, and resonance concepts aren’t the fundamental mechanism for metal detection in inductive sensors.

The sensing principle is electromagnetic induction. An inductive proximity sensor uses a coil driven by an oscillator to emit an alternating magnetic field at the sensing face. When a metallic object comes into range, eddy currents are induced in the metal. These currents create their own magnetic field that opposes the original field, changing the coil’s impedance (and often the oscillator’s frequency or amplitude). The sensor detects this change and switches its output. This approach is specifically suited to metal targets and works without any physical contact. Capacitance-based sensing responds to changes in dielectric properties, photoelectric sensing relies on light, and resonance concepts aren’t the fundamental mechanism for metal detection in inductive sensors.