Switching circuit for a remote control system
US4377754A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 26, 1981 |
| Grant date | Mar 22, 1983 |
| Priority date | — |
| Expiry date | Feb 26, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY04S40/121
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The switching circuit couples an appliance (1) to a power main (LN) via remotely controllable switching means (2) and is operable to change the state of the switching means (2) in response to a manual double switching of the appliance power switch so that the appliance can be manually switched ON after it has been remotely switched OFF. A capacitor (CAP1) generates from the mains voltage an alternating current signal of a phase differing from that of the mains voltage by an amount dependent on the external impedance across the output. The switching circuit monitors this phase difference and changes the state of the switching means (2) if it detects two phase difference changes exceeding a predetermined value in opposite senses within a predetermined time period, this being indicative of a manual double switching of the appliance power switch. The switching circuit does not operate spuriously for thermostatically controlled appliances nor in response to noise spikes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.