×

Displacement converting circuit arrangement

  • US 4,389,646 A
  • Filed: 03/31/1981
  • Issued: 06/21/1983
  • Est. Priority Date: 04/30/1980
  • Status: Expired due to Term
First Claim
Patent Images

1. A displacement converting circuit arrangement comprising:

  • first and second impedance elements, the impedance of at least one of said elements being variable in response to a mechanical displacement thereof;

    means for deriving first and second DC currents, said first and second DC currents being proportional to the impedances of said first and second impedance elements, respectively;

    means for deriving a current corresponding to the sum of said first and second DC currents;

    a field effect transistor having said current corresponding to the sum of said first and second DC currents flowing between its source and drain electrodes, said field effect transistor maintaining said sum current at a constant value;

    means for maintaining at least one of said first and second DC currents at a fixed amount;

    a differential amplifier having first and second input terminals and an output terminal, said first and second DC currents being supplied to the first and second input terminals respectively of said differential amplifier; and

    an output transistor coupled to the output terminal of said differential amplifier, the current at the output of said output transistor corresponding to the difference between said first and second DC currents, said output current indicating the magnitude of said mechanical displacement.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×