Active impedance multiplier
US3946279A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 1974 |
| Grant date | Mar 23, 1976 |
| Priority date | — |
| Expiry date | Dec 10, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/17
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An active impedance multiplier circuit that can, as one of its uses, be used in a mine ground fault detection system. The purpose of the multiplier is to create a very high impedance for an AC signal that normally flows through a low impedance legitimate load. To accomplish this, the output of the multiplier is put in parallel with the low impedance load and impresses upon the load an appropriate voltage and current. When used in a fault detecting system, the impedance multiplier will act to normally prevent current from flowing in the low impedance load. AC current will flow to the legitimate load from the multiplier in response to signals obtained from an alternating current detector located within each multiplier. In its most basic form, the active impedance multiplier can be said to consist of a current detector and a current amplifier to amplify the detected current by a constant factor. The amplified output from the multiplier is in turn connected in parallel across the legitimate load.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.