A proximity sensor, comprising: a variable gain oscillator adapted to receive electrical energy, the variable gain oscillator including a sensor coil and having a gain that varies with proximity of a target to the sensor coil, the variable gain oscillator coupled to receive a feedback signal and configured, in response to the feedback signal, to generate an oscillating electrical signal having a substantially constant amplitude magnitude and generate an energy signal representative of the electrical energy received by the variable gain oscillator; a feedback circuit coupled to receive the oscillating electrical signal and configured, in response thereto, to supply the feedback signal; a proximity determination circuit coupled to receive the energy signal and configured, in response thereto, to supply a proximity signal representative of the target Proximity to the sensor coil; and a health monitor circuit coupled to receive the oscillating electrical signal and configured, in response thereto, to supply a health status signal representative of the proximity sensor health, characterised in that the variable gain oscillator comprises: a resonant tank circuit including the sensor coil, and a transistor circuit connected to the resonant tank circuit, the transistor circuit including a bipolar transistor having a base terminal, a collector terminal, and an emitter terminal, the collector terminal coupled to the feedback circuit to thereby supply the oscillating electrical signal thereto, the emitter terminal coupled to the proximity determination circuit to thereby supplying the energy signal thereto. a variable gain oscillator adapted to receive electrical energy, the variable gain oscillator including a sensor coil and having a gain that varies with proximity of a target to the sensor coil, the variable gain oscillator coupled to receive a feedback signal and configured, in response to the feedback signal, to generate an oscillating electrical signal having a substantially constant amplitude magnitude and generate an energy signal representative of the electrical energy received by the variable gain oscillator; a feedback circuit coupled to receive the oscillating electrical signal and configured, in response thereto, to supply the feedback signal; a proximity determination circuit coupled to receive the energy signal and configured, in response thereto, to supply a proximity signal representative of the target Proximity to the sensor coil; and a health monitor circuit coupled to receive the oscillating electrical signal and configured, in response thereto, to supply a health status signal representative of the proximity sensor health, characterised in that the variable gain oscillator comprises: a resonant tank circuit including the sensor coil, and a transistor circuit connected to the resonant tank circuit, the transistor circuit including a bipolar transistor having a base terminal, a collector terminal, and an emitter terminal, the collector terminal coupled to the feedback circuit to thereby supply the oscillating electrical signal thereto, the emitter terminal coupled to the proximity determination circuit to thereby supplying the energy signal thereto. a resonant tank circuit including the sensor coil, and a transistor circuit connected to the resonant tank circuit, the transistor circuit including a bipolar transistor having a base terminal, a collector terminal, and an emitter terminal, the collector terminal coupled to the feedback circuit to thereby supply the oscillating electrical signal thereto, the emitter terminal coupled to the proximity determination circuit to thereby supplying the energy signal thereto.