Current controlled electronic circuit for a hot wire air flow meter
US4938061A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 1988 |
| Grant date | Jul 3, 1990 |
| Priority date | — |
| Expiry date | Sep 30, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F1/698
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A current controlled electronic circuit for a hot wire air flow meter having a symmetrical bridge circuit to measure the mass of the airflow. The present current bridge arrangement requires very few adjustments to select a few resistors for obtaining a required temperature differential and compensation for variations in the temperature coefficient of resistance of both the heated and cold resistors. This is accomplished by placing of a voltage divider in parallel with the sensing leg and a first amplifier responding to the voltage divider and the sensing let to control the current in the compensation leg. A second amplifier responds to the compensation leg for controlling the power to the sensing leg.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.