| 摘要 |
<p>The capacitive touch plate semiconductor switch, for keyboards, is simple and cheap and has a touch plate (11) with metal coatings (10, 12) on each side of its insulating main body. One coating is touched by the users finger and the other is connected to the base input of a transistor amplifier (24). The transistor is connected by its emitter to a signal generator (16), by its collector to the output load (20), and by its base to the touch plate capacitor. The transistor has its base emitter junction shunted by a capacitor (26) and by a resistor (28). The transistor may be replaced by a differential amplifier.</p> |
