EC-Lab Technical Notes 35: Bandwidth selection

Introduction

The stability factor or bandwidth has been explained in the application note #4 but this parameter is often not well handled/understood. In simple terms, bandwidth deals with how fast the instrument is able to react. This is the regulation loop of the instrument, specifically the regulation loop of the control amplifier (CA).

The three main parameters that affect the regulation loop (the bandwidth selection) are:

• The cell itself (represented by Z2 in Fig. 1). Slow bandwidth is usually recommended for capacitive cells,
• The range of current set (represented by Z1 in Fig. 1). If the user needs a current booster, the instrument has to be slowed down, so slow bandwidth has to be reduced, and
• The control mode. Potentiostatic or Galvanostatic.