Mumbai university > FE > SEM 1 > Applied Physics 1

Marks: 5M

Year: May 2014

Principle-

Piezoelectric oscillator works under the principle of Inverse piezoelectric effect.

Construction-

Working-

1) When a pressure is applied along the mechanical axis of crystal with respect to optic axis electrical charges are produced along the electrical axis. This is known as piezoelectric effect.

2) When an emf is induced along the electrical axis of crystal with respect to the optic axis, the crystal will get distorted along the mechanical axis. This is known as inverse piezoelectric effect.

3) At resonance ultrasonic waves will be produced. The condition for resonance is –Natural frequency of crystal = Frequency of oscillator circuit

= $\frac{K}{2l}\sqrt{\frac{γ}{ρ}} = \frac{1}{2π\sqrt{L_1C_1}}$

Here, K=1,2,3… it depends on the fundamental the first & second overtone.