| 摘要 |
An electronic device intended to supply an electric control signal in response to the momentary application of an impedance which may be constituted by the impedance of the human body between an input terminal and earth. The device comprising a single active amplifier element in a feedback oscillator in which the feedback circuit is completed, for example, by being touched. The active member is biased in class C so that it is virtually blocked until oscillations set in by closing the feedback circuit with the human body whereupon the active element passes into class A condition. The control signal is formed by the average current of the active member resulting from amplification of the detected oscillations on the input electrode of the active element. This single amplifier stage produces simultaneously a feedback of the high frequency current, a detection of the peaks of this high frequency current and an amplification in direct current of the detected current, the state of oscillation continuing or not, according to a chosen mode of operation after the said impedence is no longer applied.
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