Load-control system responsive to operating condition of producer of intermittent radiation
US3932742A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Mar 7, 1973 |
| Grant date | Jan 13, 1976 |
| Priority date | — |
| Expiry date | Mar 7, 1993 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B47/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The operating condition of a producer of intermittent radiation, such as a motion-picture projector or a television receiver, is monitored by a detector circuit including a photoelectric transducer followed by a filter with a pass band centered on the interruption frequency. The detector output is used to control the lighting of a lamp or the drawing of a curtain in a room where ambient illumination is to be suppressed or reduced during operation of the monitored apparatus. In one embodiment, the band-pass filter is inserted in a negative-feedback loop which suppresses the frequencies falling within its pass band. A band-stop filter may be connected in cascade with the band-pass filter to block the passage of signals due to other radiation such as ambient artificial light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.