| 摘要 |
This switching device has a presence indicator which can be influenced from the outside, for example an oscillator, with an electronic switch (12) which can be controlled by the presence indicator, possibly via a switching amplifier, for example a transistor, a thyristor or a triac, and with a hysteresis resistor (14), a hysteresis current flowing via the hysteresis resistor (14) in the influenced state of the presence indicator, in such a manner that the sensitivity (operating or influencing sensitivity) of the presence indicator is greater than in the uninfluenced state. In detail, the switching amplifier following the presence indicator exhibits a threshold transistor (15) operated in common-emitter circuit, and a hysteresis transistor (16), and the hysteresis resistor (14) is located both in the base-emitter circuit of the threshold transistor (15) and in the collector-emitter circuit of the hysteresis transistor (16). For the switching device discussed to have a largely constant hysteresis, the hysteresis current flowing via the hysteresis resistor (14) is regulated, preferably by means of a regulating transistor (17) being provided, the collector-emitter path (19) of the regulating transistor (17) being connected to the base (18) of the hysteresis transistor (16) (and to the reference potential), and the base (20) of the regulating transistor (17) being connected to a ... Original abstract incomplete.
|
