Production of ultrasonic waves by Galton Whistle method
Ultrasonics can be produced by means of (i) Galton’s Whistle (ii) Magnetostriction Generator (ii) Piezoelectric Generator or Oscillator.
Galton’s Whistle. It contains of essentially a short cylindrical pipe blown in the form of an annular nozzle. The distance of nozzle from the edge of pipe can be varied by turning a micrometer screw. By suitable adjustment of this distance and the pressure of air blast, the pipe is set into resonant viberation at a frequency depending on length and diameter of pipe. The Galton’s Whistle method can be used to produce ultrasonic waves of low frequency upto 100kHz.
I will discuss the other methods in next articles.