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Electronic parking meter

  • US 8,727,207 B1
  • Filed: 10/23/1997
  • Issued: 05/20/2014
  • Est. Priority Date: 04/06/1995
  • Status: Expired due to Term
First Claim
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1. A proximity detector for detecting the presence of a coin or token in a coin chute comprising:

  • a first oscillator circuit having a first coil and a first capacitor;

    a second oscillator circuit having a second coil and a second capacitor;

    said first and second oscillator circuits being inductively coupled;

    said coils and said capacitors having substantially the same values;

    said coils being axially aligned with one another and being disposed on opposite sides of said coin chute;

    a common-emitter amplifier having a base and a collector, said collector providing a detector output, one of said first and second coils being connected to said collector and the other of said first and second coils being connected to said base.

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