Conductivity measuring instrument having linearization means and a digital read-out
US4074186A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 19, 1975 |
| Grant date | Feb 14, 1978 |
| Priority date | — |
| Expiry date | Sep 19, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R27/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Conductivity measuring instruments are provided in which a test coil is supplied with alternating current and a detector responds to the voltage across the test coil to develop an analog voltage which is applied to a linearization circuit to develop an output voltage as a linear function of conductivity, the output voltage being applied to a digital read-out unit. As a function of conductivity, the analog voltage is single-valued, preferably with no more than a gradual slope change over a wide range of conductivity values. In one embodiment, a high impedance is provided in series with the test coil, the detector is a phase detector operated to respond primarily to the inductive component and linearization circuit is of a diode-function type. Alternatives are in the use of a phase-to-voltage type of detector and in the use of a digital type of detector and in the use of a digital type of linearization circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.