Circuit for Quartz Micro Balance

Hi Everyone,

I am basically being screwed in my PhD and not being given the equipment I need. I must have 3 quartz microbalances to measure deposition rate of 3 material sources. I have the crystals and something to mount them inside the chamber, but they won't buy any more equipment to measure the frequency difference.

So I have to fund it myself. That means I would like a solution that is cheap, but reliable enough to deposit some thin films. Also, I would like something as basic as possible. I would rather lose a little performance and it be simple than have high performance and added complication.

Has anyone a circuit design for such a device or even made one themselves?

Thanks for any suggestions or help.
Alex