Posted on Feb 6, 2014

Simple opamp circuit with one transistor gives reliable hot-wire anemometer for measuring flow of gases or liquids. R2 is heated above ambient temperature in Wheatstone bridge including overheat resistor R1which is calibrated to be 30% larger than cold resistance of R2. Bridge is fed from power tran. sistor which is within feedback loop of opamp th

Click here to download the full size of the above Circuit.

at senses bridge unbalance. Output of bridge is fed back to power transistor in correct phase for maintaining constant- temperature condition in which R2 is approximately equal to R1. Article covers construction of hot-wire probe made from Wollaston wire. -W. Bank, Build Your Own Constant-Temperature Hot-Wire Anemometer, EDN Magazine, Aug. 1, 1972, p 43.

Leave Comment

characters left:

Related Circuits

  • New Circuits



    Popular Circuits

    Circuit transmits ARINC 429 data
    Light-Wave Voice-Communication Receiver Circuit
    LED dimmer circuit
    Free Running Oscillator Circuit
    Incorrect frequency from crystal oscillator
    low cost buffered voltage reference
    Schematic Diagram 50W TK4036II baseed Stereo Power Amplifier Circuitand explanation
    High dynamic range CMOS (HDRC) imagers for safety systems
    100W amplifier circuit
    Subcutaneous Transmitter
    300W Valve RF Transmitter circuit