Electric switch

• US 4,121,113 A
• Filed: 04/11/1977
• Issued: 10/17/1978
• Est. Priority Date: 04/11/1977
• Status: Expired due to Term

• Current Assignee: Tektronix Incorporated (Fortive Corp.)
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: White, Robert Edward, Moeckli, David Edward
• Primary Examiner(s): Rubinson, Gene Z.
• Assistant Examiner(s): Ginsburg, Morris
• Application Number:
  US05/786,000
• Time in Patent Office: 554 Days
• Field of Search: 307/112, 307/113, 307/114, 307/115, 307/116, 307/117, 307/118, 307/119, 307/252 B, 307/140, 361/100, 340/147 R, 323/19, 323/24, 323/34
• US Class Current: 307/140
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H03K 17/723 using transformer coupling
• CPC Class Codes: Y10S 323/909 Remote sensing

Abstract

An electrical switch which can be remotely conditioned to an ON state or an OFF state for controlling the energization of a load with a single isolating component providing both control and power functions.

Claims

1. A remotely activated electrical control circuit for applying power to a load, the circuit comprising:

switch means connected to an alternating current power supply and in series with the load for switching power to the load;

control means for controlling the conduction and non-conduction of said switch means, said control means being isolatively coupled to said alternating current power supply and said switch means;

said control means includes a transformer with a first winding for applying a control voltage to said switch means for turning it on and off and also includes a control section for selectively shorting a second winding of said transformer; and

said control section includes a full-wave rectifier connected between the output terminals of said second winding of said transformer for providing a DC voltage to activate said control means.

2. The electrical control circuit according to claim 1 wherein said control means is deactivated by shorting said output terminals of said second winding of said transformer.

3. The electrical control circuit according to claim 2 wherein said control section includes:

a first transistor having the emitter connected to one terminal of said full-wave rectifier;

a second transistor of opposite conductivity to said first transistor having the collector, base, and emitter thereof connected to the base and collector of said first transistor and the other terminal of said full-wave rectifier, respectively;

first and second resistors connected in series with each other between said one terminal of said full-wave rectifier and the collector of said first transistor; and

external means for electrically connecting or disconnecting the junction point of said first and second resistors to said other terminal of said full-wave rectifier, thus shorting the output terminals of said second winding of said transformer.