Electronic timer using zero power while off
US5508878A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 2, 1994 |
| Grant date | Apr 16, 1996 |
| Priority date | — |
| Expiry date | Mar 2, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/40
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus interrupts a circuit at a predetermined time. The circuit includes a load and a source of time-varying current. The apparatus includes a relay circuit including a latching relay switch, a first relay coil and a second relay coil, the relay switch switching to engage a first current path when energy is applied to the first relay coil, the relay switch switching to engage a second current path when energy is applied to the second relay coil. The apparatus further includes a switch coupled with the relay means for selectively completing the circuit through one current path of the first current path and the second current path. The apparatus further includes a power supply responsive to the time-varying current for generating a reference voltage, and a timer for measuring a time factor in response to the reference voltage. The apparatus further includes a control circuit coupled with the power supply and the relay circuit and receiving a timeout signal from the timer, the control circuit responding to the timeout signal by applying energy to one relay coil of the first relay coil and the second relay coil, the relay switch switching when the energy is applied to the one re…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.