Transducer combining comparator or converter function with sensor function
US4206646A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1978 |
| Grant date | Jun 10, 1980 |
| Priority date | — |
| Expiry date | Sep 27, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K7/01
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A transducer is disclosed which provides a digital indication of a sensed analog condition without the need of an analog to digital (A/D) converter or a comparator. A condition responsive element having a true abrupt switching characteristic at a known breakover voltage as a function of a condition being sensed is biased by a voltage source preferably supplying a periodic voltage as a known function of time. The point during the voltage source cycle at which the condition responsive element switches to its other state is determined by the sensed condition. Preferably, a clock of known frequency is enabled when the condition responsive element is in one of its states, whereby clock pulses are counted during an interval whose duration is determined by the sensed condition. The number of clock pulses counted is a digital value of the analog condition being sensed because: (i) the clock frequency is known; (ii) the voltage/time relation of the voltage source is known; and (iii) the voltage/sensed condition relation of the condition responsive element is known. A thermally sensitive thyristor is specifically disclosed for the condition responsive element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.