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BELL SYSTEM TECHNICAL JOURNAL 



Fig. 12.1 — Nicolson's crystal oscillator circuit 



Fig. 12.2 — Cady's oscillator circuit using a crystal as a "mechanically tuned 

 feedback path" 



Fig. 12.3 — Equivalent electrical circuit of a piezoelectric crystal near its 

 resonant frequency 



two-electrode crystal connected between grid and cathode and no tuned cir- 

 cuit, where the operation would not be satisfactorily explained by Cady's 

 method. His circuits would require the crystal to exhibit inductive react- 



