Automatic Gain Controller (AGC) for Quartz crystal driver in liquid

Thread Starter


Joined Feb 2, 2015
Hi everybody,

I'm having trouble for driving a quartz crystal in liquid environment. This is a QCM (quartz crystal microbalance) application. When we use a Pierce Oscillator circuit everything is fine in the air. However, in liquid environment oscillator is damped very easily or lose stability. OpenQCM is a nice application for this. However, the liquid cell and driver electronic must match very well (at least my assumption and out of other possible effects). For our case Pierce oscillator looks not capable of driving the crystal in liquid. Thus I would like to use an automatic gain controller (AGC) to make the oscillation amplitude stable.

I need some support related to this issue. How can I connect Pierce oscillator and AGC or can I drive the crystal directly using AGC? i couldn' t achieve to find a sample schematics. Any suggestion for AGC (probably an IC )? and anything else you think can be helpful for my issue.

Thanks in advance

Best regards