Linear oscillator for proximity sensor
US4001718A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 12, 1975 |
| Grant date | Jan 4, 1977 |
| Priority date | — |
| Expiry date | May 12, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/9547
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A proximity sensor oscillator, having a resonant circuit in which the power loss is inversely related to the distance of a conductive body from a probe containing a part of the resonant circuit, produces an oscillating output signal in the resonant circuit with a peak amplitude that varies with power loss and distance. A power source provides either the current or the voltage component of electrical power at a substantially constant value independent of changes of resonant circuit power loss and is periodically switched to the resonant circuit to provide an average input power thereto. The power loss of the resonant circuit loads the source, and thus the other component of power oscillates within the resonant circuit at a peak amplitude linearly related to the inverse of the power loss. A control circuit is responsive to the phase of the oscillating component to maximize power input to the resonant circuit by applying the fixed power component substantially only throughout each alternate half wave of the oscillating component having the same polarity sense as the one component. Over the operating range where the inverse of the power loss has a linear variation with distance, the pe…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.