The mystery of potentiostat stability explained (Potentiostat stability) – Battery – Application Note 4Latest updated: August 31, 2021
The role of a potentiostat/galvanostat is to apply a desired potential/current and measure the current/potential response in any situation, even the most difficult for example when the current range increases of 6 orders of magnitude. The bandwidth of the instrument, which is the rate at which the potentiostat can respond to a change in the system, is of critical importance. Bio-Logic instruments have adjustable bandwidths and this note explains why a potentiostat can start to oscillate in certain conditions and how the choice of the ad hoc bandwidth can eliminate these oscillations.
Like the vast majority of research instruments, potentiostats are seldom used in trivial experimental conditions.
Potentiostat/galvanostats do not only have to deal with a vast, highly eclectic range of research activities, but also wide-ranging electrochemical systems and experiments.
Furthermore, due to their nature, the electrochemical experiments evolve over extremely large ranges of values of the significant parameters.
In corrosion applications, for example, recording the current over 5 or 6 current ranges in the same experiment is very common. It is not hard to imagine that, in such a demanding environment, potentiostats are often pushed to their limits and used in situations that may compromise their performance. There are always times when potentiostats do not function as expected. Ringing or oscillations, for example, are signs that a potentiostat is struggling to maintain or has even lost control of the cell’s potential.
This document’s aim is to clarify the origins of the stability problems of such instruments using the example of the VMP3 multichannel potentiostat.
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