Electronic monitoring system with Zener diode to control capacitor charging current
US4100479A · kind A · utility
Inventor
Key dates
| Filing date | Apr 12, 1977 |
| Grant date | Jul 11, 1978 |
| Priority date | — |
| Expiry date | Apr 12, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/30
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A contactless motion detector, such as an oscillator sensitive to an approaching metallic element, is connected across a storage capacitor which can be charged from a source of pulsating direct current through a constant-current unit. A Zener diode, shunting the storage capacitor and part of the constant-current unit in series therewith, throttles the flow of charging current through that unit when the capacitor reaches a predetermined charging voltage. Connected across the series combination of storage capacitor and constant-current unit is an ancillary thyristor, triggerable by the detector, forming part of a firing circuit for a main thyristor in parallel therewith; that firing circuit further includes another Zener diode and a stabilizing resistor in series with the ancillary thyristor. Conduction of the main thyristor, upon the triggering of the ancillary thyristor, reduces to near-zero the resistance in series with a load, such as a relay, which is traversed by the current drawn from the source. With both thyristors cut off between pulsations of the source current, the storage capacitor is briefly recharged through a decoupling diode upon a retriggering of the ancillary thyri…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.