Lamp outage indicator circuit
US4190830A · kind A · utility
21Cited by
8References
4Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 12, 1978 |
| Grant date | Feb 26, 1980 |
| Priority date | — |
| Expiry date | Oct 12, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An indicator circuit for indicating whether an incandescent type lamp is burned out. The indicator circuits include a voltage reference source and an indicator LED which is normally biased just below the knee of its conduction curve, but which is biased into conduction whenever the monitored lamp burns out. A bridge circuit is utilized so that relatively small variations in power source voltage do not affect the operating point of the circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.