3
Chapter 1 — INTRODUCTION
Fig. 1. Potentiostat-Mode Block Diagram.
Fig. 2. Galvanostat-Mode Block Diagram.
1.4.2. Galvanostatic Mode
In galvanostatic operation, the PARSTAT 2273 controls the current between the counter and
working electrodes at the specified fraction of the selected current range (up to the maximum of
100% the current range; see Fig. 2).
The counter electrode is driven to the potential required (consistent with the ±100 V compliance of
the control amplifier) to establish the desired cell current. The reference electrode is not used in
the control loop, but is usually used to measure the potential at some point in the electrochemical
cell.
1.5. Polarity Convention
The PARSTAT 2273 hardware follows the American polarity convention. Positive current is
cathodic; that is, a current is defined as positive if reduction is taking place at the working
electrode. Negative current is anodic; that is, a current is defined as negative if oxidation is taking
place at the working electrode. If the working electrode is driven positive with respect to the