| 摘要 |
The sensor electrode (S) is formed by a conductive sensor face, which is supplied with an AC voltage signal by an oscillator (1), whose demodulated output signal (A) is fed to a threshold value switch (4). The proximity switch switching distance is adjustable by the oscillation supply voltage (40B), also adjustable by a potentiometer (R11). Preferably the potentiometer is incorporated in front of an operational amplifier (OP) and is located in a reference voltage divider circuit, i.e. a resistance network (R7-9, R11), whose output voltage is a function of the oscillator operating voltage over the switching distance, when the switching threshold value has been attained. |
