The jet is accelerated towards the counter electrode.

The insulator layer serves the purpose of increasing the contrast ratio and separating the working electrode electrically from the counter electrode.

A conducting carbon layer is typically used as the conductive back contact for the counter electrode.

The counter electrode, also known as the auxiliary or second electrode, can be any material which conducts easily and won't react with the bulk solution.

To maintain the observed current the counter electrode will often oxidize or reduce the solvent or bulk electrolyte.

The counter electrode is usually made of an inert material, such as a noble metal or graphite, to keep it from dissolving.

Diffusion of the oxidized form of the shuttle to the counter electrode completes the circuit.

And the electrons finally reach the counter electrode through the circuit.

In order to form an effective schottky contact, the electron affinity(E) must be smaller than the work function(φ) of the metal composing the counter electrode.

In VING with partial contact, the geometry of the counter electrode plays an important role.