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Inductive amplifier having automatic gain control for butt set

  • US 5,574,769 A
  • Filed: 11/09/1995
  • Issued: 11/12/1996
  • Est. Priority Date: 11/09/1995
  • Status: Expired due to Term
First Claim
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1. An inductive amplifier for detecting and amplifying an electrical tone conducted by one of a group of wires in order to identify and trace a particular wire, said inductive amplifier comprising in combination:

  • a. a housing;

    b. an electrically conductive probe extending from the housing for being placed adjacent a wire under test to detect an electrical tone signal therein;

    c. a variable gain amplifier contained within the housing to amplify the detected electrical tone signal, the variable gain amplifier selectively providing a first level of gain or a second level of gain;

    d. a speaker disposed in the housing for reproducing the amplified electrical tone as an audible signal;

    e. butt set terminals extending from the housing and adapted to be coupled with leads of a telecommunications butt set for allowing a speaker within an earpiece of the telecommunications butt set to reproduce the amplified electrical tone as an audible signal; and

    f. a butt set lead detection circuit for detecting that the leads of the butt set are connected to the butt set terminals, and for causing the gain of the variable gain amplifier to decrease from the first level of gain to the second level of gain when the leads of the butt set are connected to the butt set terminals.

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