Lamp control responsive to rapid increases in ambient light
US5892331A · kind A · utility
Inventor
Key dates
| Filing date | Mar 4, 1996 |
| Grant date | Apr 6, 1999 |
| Priority date | — |
| Expiry date | Mar 4, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A lamp control apparatus that responds to sudden increases in ambient light by energizing a light bulb for a short period of time. A first voltage comparator is connected to a photocell circuit such that its output normally presents a high impedance to a timing capacitor connected to the input of a second voltage comparator which, in turn, provides a gate signal for a triac power switch. The first comparator will switch to a low impedance output if a sufficient amount of light suddenly appears at the photocell. This low impedance will rapidly discharge the timing capacitor and allow the second comparator to energize the lamp. The timing capacitor will then slowly charge back to a voltage that will cause the second comparator to remove the gate signal for the triac, thereby de-energizing the lamp.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.