Electronic relative humidity/temperature measuring system
US5040417A · kind A · utility
Inventor
Key dates
| Filing date | Nov 13, 1989 |
| Grant date | Aug 20, 1991 |
| Priority date | — |
| Expiry date | Nov 13, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K7/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The disclosure relates to a system for measuring relative humidity and temperature wherein there are provided three controlled switching matrices, a first of the matrices determining whether a current for determining temperature or relative humidity is to be fed via a diode to a system voltage output from when the voltage output will be converted to an appropriate temperature or relative humidity reading. The remaining two matrices are each controlled by an oscillating voltage which alternates the output or input terminal thereof depending upon whether the oscillating voltage is positive or negative. This causes current to be passed through a humidity responsive resistor in opposite directions during each half cycle of the oscillating voltage. In the case of humidity sensing, the diode used for measuring temperature also acts as a temperature compensating device for the humidity sensor, thereby having a dual function in the system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.