Scanning Vibrating Electrode Technique (SVET)

The Scanning Vibrating Electrode Technique uses a single wire to measures voltage drop in solution. This voltage drop is a result of local current at the surface of a sample. Measuring this voltage in solution images the current at the sample surface. Current can be naturally occurring from a corrosion or biological process, or the current can be externally controlled using a Galvanostat. A piezo unit vibrates the probe in Z-direction (axis parallel to the sample). The amplitude of vibration may be only 10s of microns peak-to-peak. This small vibration provides a very small voltage to be measured. Therefore, the response (signal + noise) at the probe is then gained by the electrometer. The gained output of the electrometer is then input to a Lock-In Amplifier. This, in turn, uses a phase detector along with a Reference at the same frequency of vibration to extract the small AC signal from the entire measured response.