Fail-off photo control circuit for night lighting
US4042853A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 28, 1976 |
| Grant date | Aug 16, 1977 |
| Priority date | — |
| Expiry date | Jan 28, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A circuit for controlling the energization of a night lighting load or the like, in which failure of the main circuit to control and shut off electrical supply to the load during daylight hours leads to permanent shutdown of the electrical supply to the load. Two photosensitive elements are provided in the circuit. One element, e.g. a photocell, is a main control which periodically operates a relay and supplies electricity to the load, i.e. at night. The second element, e.g. a second photocell, is connected in the circuit, together with a second relay, in such a manner that failure of the first relay to operate and open the load circuit during daylight hours will cause the second relay to operate and permanently open the load circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.