In customized potentiostat, below given circuit are used.

The electrochemical cell description is as per below.

Working Electrode

Platinum

Reference Electrode

Ag-Agcl

Counter Electrode

Platinum

Electrolyte

Ferro/Ferri with KCL (1:1)

Scan Rate

50mV/Sec

Scan Potential

-200 mV to 700 mV

The source voltage is -1V to +1V (mentioned in circuit) but generally we are using -0.2V to +0.6V as scanning voltage. During scanning (-0.2V to +0.6V), I have measured the voltage between working electrode (WE) and reference electrode (RE) which is -0.4 to +0.8V (approx.)which should be -0.2V to +0.6V and this is happened due to electrolyte (solution resistance).

The circuit may need to improve by taking feedback from WE & RE to make it exact -0.2V to +0.6V.

I want few suggestion for circuit improvement.