The Coefficient of the Voltage Induced Frequency Shift Measurement on a Quartz Tuning Fork

• Main Authors: Yubin Hou, Qingyou Lu
• Format: Article
• Language: English
• Published: MDPI AG 2014-11-01
• Series: Sensors
• Subjects: qplus; quartz tuning fork; piezoelectric frequency effect; eigen-frequency shift; voltage induced frequency shift
• Online Access: http://www.mdpi.com/1424-8220/14/11/21941

We have measured the coefficient of the voltage induced frequency shift (VIFS) of a 32.768 KHz quartz tuning fork. Three vibration modes were studied: one prong oscillating, two prongs oscillating in the same direction, and two prongs oscillating in opposite directions. They all showed a parabolic dependence of the eigen-frequency shift on the bias voltage applied across the fork, due to the voltage-induced internal stress, which varies as the fork oscillates. The average coefficient of the VIFS effect is as low as several hundred nano-Hz per millivolt, implying that fast-response voltage-controlled oscillators and phase-locked loops with nano-Hz resolution can be built.