Acoustic thermometer


Posted on Feb 7, 2014

Acoustic thermometry is used where extremes in operating temperature are encountered, such as in cryogenics and nuclear reactors. The transducer is composed of Polaroid ultrasonic material, mounted at one end of a sealed, 6-in long Invar tube. The medium inside the tube is dry air. The transducer can be considered a capacitor, composed


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

of an insulating disc with conductive coating on each side. Each clock pulse causes mechanical movement of the disc, and ultrasonic energy is emitted. The clock pulse simultaneously resets the 74C74 output flip-flop. The ultrasonic energy travels down the tube, bounces off the far end, and returns to the transducer, causing mechanical displacement of the transducer. This shifts the transducer capacitance, resetting the 74C74 through A2 and C1. The 74C74 output pulse represents the transit time down the tube and it varies with the temperature, according to the equation: The pulse width (time between set and reset) can be converted into desired temperature information with a monitoring processor. Linear Technology. Linear Applications Handbook 1990. p AN7-5,





Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Five-transistor amplifier
    On-off controller
    Switch Timer For Bathroom Light
    Compensation Resistor Stabilizes SMPS at High Duty Cycles
    amplifier How does this circuit attenuate high frequencies
    digital to analog
    3v fm transmitter circuit
    Ultra-Simple Microphone Preamplifier
    12AX7/12BH7 Hammond Tube Preamp Project
    LED sequencer
    Domestic Seismic Alarm



    Top