M.A.F Sensor Circuit Operation

Please read the entire description as there are points of clarification/correction...Part 2 of 3. Hot Wire type is under consideration. In painful detail! Part 3 to follow. Please consider watching part one (outlining how changes in air flow affect cooling on the hot wire can be exploited for monitoring purposes) if this concept is alien to you...Link to part 1...   • MAF Sensing Concept Part 1  
A more open throttel and hi RPM imposes a high degree of cooling on the "Hot Wire".
Idle and lower (& over run) RPM imposes a lower degree of cooling on the "Hot Wire".
The circuits "desire" to maintain the DeltaT. between the Hot and Reference (Cold Wire) thermistors results in a Voltage output to the ECM correlating to Engine Mass Air Flow. Note: While both bridge thermistors are PTC type, the IAT thermistor is NTC. Apologies for my use of the terms Reference, Cold Wire and Compensation Thermistor as interchangeable. I will endeavour to maintain consistent terminology in future efforts.
**Correction** On a few occasions I mention (or even on a graphic) the Transistor turning "Off"...this is never the case...The Transistor is always conducting...
Sometimes more so (greater heat, base ++) sometimes less so (lower heat, base +)
In Part 3...we "look" @ the signals on the Picoscope...Cheers
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