| 摘要 |
An oscillator/demodulator circuit for an inductive proximity switch includes a transistor amplifier stage having an input circuit and an output circuit, a resonant circuit connected in the input circuit of the transistor amplifier stage, a device for damping the resonant circuit, a device for providing positive feedback from the output circuit to the input circuit of the transistor amplifier stage, a limiter branch connected in the input circuit of the transistor amplifier stage, a dual current mirror active in the input circuit of the transistor amplifier stage having first and second interconnected current mirrors including transistors. It further has a circuit output connected to the current mirrors for receiving currents supplied by the current mirrors being subtracted from each other, the transistors in the second current reflector having a larger emitter area ratio than the transistors in the first current mirror, and a resistance network connected to the oscillator/demodulator circuit output being switchable for providing an adjustable hysteresis.
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