Electrochemical measurement system having interference reduction circuit
US5220920A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 8, 1991 |
| Grant date | Jun 22, 1993 |
| Priority date | — |
| Expiry date | Nov 8, 2011 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61M5/1723
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for electrically measuring certain chemical characteristics of electrically-conductive fluids, such as blood, located within a tube and subject to electrical current interference. The measurements are made by measuring the voltage potential between a reference electrode and a sensor electrode sensitive to a particular blood parameter such as pH or calcium, potassium or chloride concentration. A bypass path for the electrical current interference is provided by a pair of noise-reduction electrodes located on opposite sides of the reference and sensor electrodes and interconnected by an amplifier having a relatively low output impedance and a relatively high input impedance. The electrical current interference bypasses the signal electrodes by flowing directly into the amplifier's output terminal, such that the reference and sensor electrodes develop a potential between them that is independent of the electrical current interference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.