Device for conversion of electrical vibrations in the ultrasound by means of a transducer of the magnetostrictive type

摘要

894,157. Magneto-strictive devices. PHILIPS ELECTRICAL INDUSTRIES Ltd. April 17, 1959 [April 22, 1958], No. 13176/59. Class 40 (4). The windings 5, 6 of magneto-strictive transducer elements 7, 8 mounted beneath a vessel 9 are energized by a polarizing alternating current Io of mains frequency and by an ultrasonic frequency current I modulated at the same mains frequency, the polarizing current Io leading in phase on the modulated current I so as to improve the efficiency. As shown, the mains frequency current source is connected to transformers 3 and 12 which provide modulating and polarizing outputs respectively, the modulating output being applied to the output stage 1 of an oscillator-amplifier 2. The leading phase angle of the polarizing current may be of the order 10 to 20 degrees, and is established by using either a choke 14 in the primary circuit of transformer 3 or by a capacitor (represented by dash-lines) in the primary circuit of transformer 12. Alternatively, a coil or capacitor may be connected in the secondary circuit of the respective transformer, or both components may be employed together.