Ferroelectrics and the Dielectric Amplifier

Ferroelectric materials are the dielectric analog of ferromagnetic materials. Their uses parallel those of ferromagnetic materials in such applications as high permeability materials, magnetostrictive transducers, magnetic amplifiers, and magnetic information storage devices. A review is given of the measured properties of single crystals to provide a background for the application of ceramics in capacitors and transducers, and their application in dielectric amplifiers. It is shown that the properties of ceramics can be stabilized by introducing amounts of lead and calcium titanate. A long-time aging effect can be reduced by a proper heat treatment. With these stabilized ceramics, applications such as electromechanical filters and delay lines can be satisfied. The theory of the dielectric amplifier is discussed and it is shown that stable amplifiers can be obtained by using the properties of single crystals. Amplifiers having carrier frequencies of 200 kc, signal frequencies of 0 to 7,000 cycles, and gains of 12 db, have been realized. These operate with single crystals below the Curie temperature and are stable over a wide temperatue range.