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US 3,947,696 AGranted
Touch actuated electronic switch
AssigneeMagic Dot, Inc.
InventorsWillis A. Larson, David E. Colglazier
Life of this patent
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AssigneeMagic Dot, Inc.
InventorsWillis A. Larson, David E. Colglazier
Estimating the term…
A touch actuated electronic switch is disclosed including a surface, accessible to the touch of a human, interconnected with a differential amplifier. In the preferred embodiment, if increased noise immunity or noise protection is desired, a twisted pair of wires is used and interconnected at one end with one wire electrically connected to the touch surface and the other substantially equal length wire being unconnected. Both wires, at the other end, are connected to the input to the differential amplifier. A common mode alternating voltage signal is then provided to the differential amplifier and a substantial alternating frequency output signal shunt is applied to the differential amplifier, in the preferred embodiment, across terminals conventionally used for D.C. offset null purposes. The output of the differential amplifier is then interconnected to an integrator, in the preferred embodiment a capacitor, and the integrator is in turn 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 the touch surface.
A touch actuated electronic switch, comprising in combination:
A touch actuated electronic switch, comprising in combination:
A touch actuated electronic switch, comprising in combination:
Dependencies are inferred from the claim text.