There is a description of potentiostat stability (written by DK Roe) in the Kissinger & Heineman book (

Converting Potentials to Another Reference Electrode

Often we find a potential listed in the literature quoted against a different reference electrode than the one we favor, or we would like to convert the potential to a more commonly used reference electrode for publication. A student emailed me: “My experiments involve measuring the redox potential relative to a saturated Ag/AgCl reference electrode. Read more about Converting Potentials to Another Reference Electrode[…]

Quartz Crystal Microbalance

The Basics of a Quartz Crystal Microbalance

This tutorial provides an introduction to the quartz crystal microbalance (QCM), which is an instrument that allows a user to monitor small mass changes on an electrode. The reader is directed to the numerous reviews1 and book chapters2 for a more in-depth description concerning the theory and application of the QCM. A basic understanding of electrical components and concepts is assumed.

The two major points of this document are:

Explanation of the Piezoelectric Effect
Equivalent Circuit Models

The Piezoelectric Effect

QCM Basics

Figure 1. Graphical Representation of Thickness Shear Deformation.

The application of a mechanical strain to certain types of materials (mostly crystals) results in the generation of an electrical potential across that material. Conversely, the application of a potential to the same material results in a mechanical strain (a deformation). Removal of the potential allows the crystal to restore to its original orientation. The igniters on gas grills are a good example of everyday use of the piezoelectric effect. Depressing the button causes the spring-loaded hammer to strike a quartz crystal thereby producing a large potential that discharges across a gap to a metal wire igniting the gas.

Quartz is by far the most widely utilized material for the development of instruments containing oscillators partly due to historical reasons (the first crystals were harvested naturally) and partly due to its commercial availability (synthetically grown nowadays). There are many ways to cut quartz crystals and each cut has a different vibrational mode upon application of a potential. The AT-cut has gained the most use in QCM applications due to its low temperature coefficient at room temperature. This means that small changes in temperature only result in small changes in frequency. It has a vibrational mode of thickness shear deformation as shown below in Figure 1.


This website uses cookies to ensure you get the best experience on our website. More information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this. Please review our Privacy Policy