thermistor based airflow sensor - opamp help

[dr pepper]

You revived a 9 year old thread, I dont think steaky has posted for a while.
To answer your question I dont think self heating the Lm35 is an option, you could if you really want strap a resistor to it and heat it that way, measuring the power required to maintain a temp would give you some idea on how much cooling the Lm is subjected too.

 

[Pommie]

If you place two thermistors in the flow. The first you just measure the resistance (and hence temperature) and the second you power to keep it's temperature a fixed amount above the first, would that give a good indication of wind speed?

Mike.
P.S. I know it's an old thread but someone is interested.

 

[osmanozyurt]

Thanks for your replies, i already put NTC thermistors in bridge, one is exposed to flow the other one measuring the ambient temperature, i got a relation between the flow and the signal (Voltage difference almost 10 times amplified via 741).