Resistance measuring system
US4413917A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 11, 1981 |
| Grant date | Nov 8, 1983 |
| Priority date | — |
| Expiry date | Jun 11, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01K7/18
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A temperature measuring system comprises a sensor which is connected to a supply rail through a first lead, and which may be selectively connected by a relay through a second lead or a third lead to the inverting input of an operational amplifier. The leads have different resistance values. The output of the amplifier is connected to its input through a resistor, and its non-inverting input is connected to the rail through a potential divider. The output of the amplifier is connected to a computer through a low pass filter and an A/D converter. In operation, the output voltage of the amplifier is first measured with the second lead connected to its inverting input and then measured again with the third lead connected. From these measurements the resistance of the sensor is calculated after calculating and hence eliminating the resistance of the leads. The sensed temperature can then be calculated from the resistance of the sensor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.