System for detecting the condition of a lamp and activating a permanent memory two-state display of the lamp condition
US5075672A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 27, 1990 |
| Grant date | Dec 24, 1991 |
| Priority date | — |
| Expiry date | Jun 27, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B47/20
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A system is provided for detecting the condition of a lamp, activating a permanent memory two-state display of the lamp condition, and displaying said condition during the daylight when no power is connected to the lamp. The system includes an electrical circuit powered by electricity drawn from power lines connected to the lamp such that the circuit is energized only when the lamp is supposed to be lighted. A rectifier transforms the alternating current of the power lines into a direct current for the circuit. The current of the power lines connected to the lamp is detected and measured when the lamp is supposed to be lighted in order to determine the condition of the lamp, and provide an appropriate signal for controlling switches within the circuit. Two alternative current pathways, each including a capacitor and a switch responsive to input from the current sensor, are provided in the circuit. When the circuit is energized, current flows through one pathway if the lamp is in working order, and through another if the lamp is sensed as being defective. The capacitor in the portion of the circuit being energized at any given time is periodically discharged to activate an electroma…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.