Crystal oscillator with piezoelectric feedback crystal - performs shear or longitudinal vibrations and has three electrodes

摘要

The crystal oscillator has a piezoelectric feedback crystal coupled to the oscillating transistor. The crystal (1) is a series resonant crystal vibrating in either a shear or a longitudinal mode but not flexural mode. The electrode (3) covering one face of the crystal is connected to a reference potential. The two electrodes on the other face of the crystal are connected one back to the oscillating transistor base and the other to its collector output and load. The common-emitter transistor (10) has its collector coupled to the large electrode of the crystal giving the reference potential. The advantage lies in using few components in conjuction with shear to longitudinal vibrations.