Control electronics for atomic force microscopy

The control electronics for the atomic force microscope (AFM) are described. The set of electronic devices described here allow convenient operation of an atomic force microscope. The key device is the force controller, which automates the otherwise tedious and time-consuming readjustment of the force to a preset value by controlling two gated feedback loops. The preset value of the force can be easily changed by simply turning a potentiometer. This automated system allows us to obtain reliable data, with known forces, despite piezoelectric creep and thermal drift in the force determining mechanical setup. The electronic devices and concepts presented here work for AFMs that use tunneling, capacitance measurements, or optical interference to sense small deflections of the spring.