Logarithmic-to-linear photocontrol apparatus for a lighting system
US4695769A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 27, 1981 |
| Grant date | Sep 22, 1987 |
| Priority date | — |
| Expiry date | Nov 27, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A photosensor for detecting the light intensity of an external light source, usually the sun, which is illuminating an area is used as the sensor for a control network of an artificial lighting system for that same area to compensate for light intensity variations. The voltage output from the photosensor is applied to a logarithmic-to-linear device which is used as an input to a comparator for producing an inverse output that drives the artificial lighting system. The logarithmic-to-linear device inserts an element into the overall control system that provides compensation that corresponds to the perceived linear light change of intensity that actually occurs when there is an actual logarithmic light change.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.