| 摘要 |
<p>A touch actuated electronic switch is disclosed including at least one surface, accessible to the touch of a human, interconnected with an active circuit and protected against static electricity. In the preferred embodiment, the active circuit is differential sensing circuitry, preferably, dual input logic circuitry, and most requiring protection from static electricity at this time, a MOS exclusive OR gate. In the preferred embodiment where the interconnection between the logic circuit and the surfaces is desired to include long wires, a twisted pair of wires is used if increased noise immunity or noise protection is desired. The twisted pair is interconnected at one end with one wire electrically connected to the touch surface and the other substantially equal length wire being unconnected or connected to a second touch surface. Both wires are connected at their other ends to the dual inputs to the logic circuitry. Also connected to the dual inputs are dual impedances which, when taken together with the impedance of the body of the human operator, provide protection against static or other high potential electricity. A common mode alternating voltage signal is then provided through input circuitry to the logic circuitry, and the output of the logic circuitry is interconnected to an integrator, in the preferred embodiment a capacitor. The integrator is, in turn in the preferred embodiment, connected to an additional amplifier. The output terminals of the additional amplifier, in the preferred embodiment, act as an electrical switch with the electrical impedance across the output terminals in a first state assuming a high impedance, electrical open circuit, or "OFF" switch condition and in the second state assuming a low impedance, electrical short circuit, or "ON" switch condition to thereby approximate the two states of a conventional mechanical electrical switch, the condition assumed by the second amplifier being dependent upon whether or not an operator has touched a touch surface.</p> |
