CERAMICS
TRANSONER
Piezoelectric Transformers
Background on Piezoelectric Transformers
How do they operate?. Resonance
70
Input Impedance open circuit conditions
Piezoelectric effect is found in Barium Titanate. However BaTiO3 is ferroelectric and piezoelectric below 120O. • PbNb2O6 and Pb(Ti,Zr)O3: Discovered in Japan early in the 1950s. These materials are usable at least to 250o. • 1954 Bernard Jaffe reported the properties of the PZT solid solution and Vernitron Corp. got the (Clevite Company Morgan Matroc Inc.) • In USA, the Piezo-industry was dominated by industrial groups with strong patents = ‘secrecy policy’ • In Japan, several companies and universities formed a ‘competitively cooperative’ association established as the Barium Titanate Application Research Committee, in 1951. • Beginning in 1965 Japanese commercial enterprises began to reap the benefits of steady application and materials development work. • 1980-Present: The commercial success of the Japanese efforts has attracted the world-wide interest for this technology and spurred a new effort to develop successful piezoceramic products.
QUARTZ
Quartz: Frequency control and highly selective electric wave filters
TRANSONER
Piezoelectric Transformers
Piezoelectricity: A brief history
• 1946:
60
1st longitudinal mode (fundamental)
Impedance [Ohms]
Piezoelectric Body
50 40 30 20 10
fA
3rd longitudinal mode
TRANSONER
Piezoelectric Transformers

Piezoelectricity: A brief of history
• Piezoelectricity derives from the Greek word “piezein” = to press.
• First human contact: “Stone Age”: use of ‘flint”, a variety of quartz, to produce fire by creating a mechanical impact or friction. Before the invention of matches this material continued being used as a lighter knocking it against iron. • 1880-81, Pierre and Jacques Curie discovered the direct (1880) and the inverse effects (1881) in quartz crystals. • 1917,during WW I, Paul Langevin developed a quartz-based transducer to generate and detect acoustic waves in water. SONAR and ULTRASONICS • Piezo-oscillator (frequency control by quartz crystals): A.M. Nicholson (Bell Telephone Laboratories) and Prof. W.G. Cady (Wesleyan University). • 1923 the Bell Telephone Laboratories established a “Quartz laboratory”, and General Electric Company did likewise the following year. • 1939 The US Armed Services made the decision to make large scale use of “crystal control” in military communication systems. During the WW II the US alone used about 50million quartz crystal elements.