Transducer employing a guard ring between input and output means to reduce stray capacitances

• US 3,219,920 A
• Filed: 04/05/1961
• Issued: 11/23/1965
• Est. Priority Date: 04/05/1961
• Status: Expired due to Term

• Current Assignee: Virgil W. Wall
• Original Assignee: Virgil W. Wall
• Inventors: Wall, Virgil W.
• Application Number:
  US04/100,973
• Time in Patent Office: 1,693 Days
• US Class Current: 340/870.37
• CPC Class Codes: G01D 5/2403 by moving plates, not forming part of the capacitor itself, e.g. shields
• CPC Class Codes: G01D 5/2415 adapted for encoders

Claims

1. IN AN ELECTROSTATIC PHASE-SHIFTING TRANSDUCER HAVING A FLAT INPUT CONDUCTOR STRIP CONTINUOUSLY ENERGIZED BY A SOURCE OF ALTERNATING CURRENT AND A FLAT OUTPUT CONDUCTOR STRIP IN COPLANAR RELATIONSHIP WITH SAID INPUT CONDUCTOR STRIP AND FLAT COUPLER MEANS IN PARALLEL OVERLYING RELATIONSHIP WITH SAID INPUT AND OUTPUT CONDUCTOR STRIPS AND SPACED THEREFROM BY A FIXED DISTANCE FOR SELECTIVELY VARYING THE PHASE OF SAID ALTERNATING CURRENT BETWEEN SAID INPUT CONDUCTOR AND SAID OUTPUT CONDUCTOR STRIPS, A FLAT GUARD CONDUCTOR INTERPOSED IN COPLANAR RELATIONSHIP BETWEEN SAID INPUT CONDUCTOR STRIP AND SAID OUTPUT CONDUCTOR STRIP, AND A CATHODE FOLLOWER, SAID GUARD CONDUCTOR BEING CONNECTED DIRECTLY TO THE CATHODE OF SAID CATHODE FOLLOWER AND SAID OUTPUT CONDUCTOR BEING CONNECTED TO THE GRID OF SAID CATHODE FOLLOWER, THE SIGNAL AT SAID GRID BEING IN PHASE WITH THE SIGNAL AT SAID CATHODE TO PREVENT SPURIOUS VOLTAGES FROM DEVELOPING ACROSS THE STRAY CAPACITANCE THEREBETWEEN THEREBY PROVIDING A PHASE SHIFTER HAVING A CONSTANT AMPLITUDE OUTPUT.