Sampled DC Polarography:

In this technique instead of recording the current continuously, it was sampled for a 5 millisecond period just before the drop falls. Between the sampling periods, the recorder was maintained at its last current level by means of a sample and hold circuit.

The main advantage of this current sampling is that it substantially reduces large current fluctuations due to continuous growth and fall of the drops at dropping electrode.

From Figure, it could be seen in which the current near the end of the life of a drop is nearly constant and it is this current only which is measured within the current sampled technique resulting in a smooth curve with extremely little current fluctuations.

Figure: Sampled DC Polarogram

LSV in that the solution or the electrode is kept in motion is called hydrodynamic voltammetry.