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Touch activated controller and method

  • US 4,321,479 A
  • Filed: 03/17/1980
  • Issued: 03/23/1982
  • Est. Priority Date: 04/19/1978
  • Status: Expired due to Term
First Claim
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1. In a touch sensitive circuit comprising an input adapted to be coupled to a sense line for supplying a change in capacitance via said input, an operational amplifier coupled to receive said change via said input, capacitance means coupled across said operational amplifier between the input and output thereof, comparator means coupled to said output of said operational amplifier, means for generating first and second signals at varying voltages normally plottable along substantially parallel traces, means for coupling said first and second signals respectively to supply signals to said operational amplifier and said comparator means to vary said output of said operational amplifier to be compared to said second signal to provide periodic cross-over between said first and second signals indicative of the presence of capacitance applied to the first named said input.

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