AC Responsive led pilot light circuitry

• US 3,869,641 A
• Filed: 10/24/1973
• Issued: 03/04/1975
• Est. Priority Date: 06/21/1972
• Status: Expired due to Term

• Current Assignee: Jack Goldberg
• Original Assignee: Jack Goldberg
• Inventors: Goldberg, Jack
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): LaRoche, E. R.
• Application Number:
  US05/409,116
• Time in Patent Office: 496 Days
• Field of Search: 315/129,130,133,135,136,169TV,227R,228,250,251,253,312 313/499,512 250/552,553 307/311,312 340/166R,166EL,248R,366E,366R,381 357/17
• US Class Current: 315/135
• CPC Class Codes: H05B 45/00 Circuit arrangements for operating light-emitting diodes [LED]
• CPC Class Codes: H05B 45/42 Antiparallel configurations

Abstract

Disclosed is light-emitting electronic circuitry including a pair oppositely poled, parallel connected diodes, at least one of which is a light-emitting diode (LED); these diodes are serially connected to a capacitor between a pair of circuit AC input terminals. The capacitor provides the necessary AC voltage drop in series with these diodes when the circuitry is connected to a source of AC line voltage, and the minimum power and heat dissipated in this circuit make it especially well suited for small package pilot light applications.

Claims

1. An LED pilot light operable from a source of AC line voltage, comprising a pair of light-emitting diodes, said diodes being connected in parallel with opposite polarity, each of said diodes generating light when properly forward biased, an enclosure having a light transmissive portion, means for supporting both of said diodes in said enclosure such that light emitted by said diodes radiates from said enclosure through said light transmissive portion in a single direction, and a capacitor having one side interconnected with said pair of diodes at one junction common to said diodes, a first circuit input terminal interconnected with the other side of said capacitor, a second circuit input terminal interconnected with the other junction common to said diodes, the capacitor voltage following AC line voltage applied to said input terminals and limiting the voltage drop across said diodes as said diodes alternately conduct on respective half cycles of said AC line voltage.

2. An LED pilot light as set forth in claim 1 wherein said capacitor is mounted within said enclosure, whereby said pilot light is entirely self-contained for direct interconnection with said source of AC line voltage.

3. An LED pilot light as set forth in claim 1 wherein said enclosure is tubular and includes a lens across one end thereof, said diodes being adapted to emit radiation through said lens.

4. An LED pilot light as set forth in claim 2 wherein said enclosure and capacitor are each cylindrical and the longitudinal axes of said enclosure and capacitor extend generally in the same direction, said diodes being supported with said enclosure at one end thereof with respect to the longitudinal axis of said enclosure, and said first and second input terminals being at the other end of said enclosure.