Describe the working of the ultrasonic magnetostriction method.

Working:

The rod is permanently magnetized within the beginning through passing direct current. Then battery is switched on and therefore current is produced through the transistor. That current is passed by the coil L that causes a consequent change into the magnetization of the rod. Currently, the rod starts vibrating because of magnetostriction effect.

While a coil is wounded over a vibrating rod, in that case e.m.f. will be inducted into the coil called as converse magnetostriction effect. Because of this effect an e.m.f. is induced into the coil L₁. The induced e.m.f. is fed to the base of the transistor that acts as a feedback continuously. During this way the current into the transistor is built up and the vibrations of the rod are maintained.

The frequency of the oscillatory circuit is adjusted through the condenser C and while this frequency is equivalent to the frequency of the vibrating rod, resonance arises. At resonance, the rod vibrates longitudinally along with larger amplitude producing ultrasonic waves of high frequency beside both ends of the rod.