Compliance Voltage: How Much is Enough

The compliance voltage of a potentiostat is the maximum voltage that the potentiostat can apply to the counter electrode in order to control the desired voltage in the electrochemical cell. The compliance voltage is generally measured as the difference between the counter electrode and the working electrode. Most potentiostat manufacturers include the compliance voltage as one of the significant specifications in their data sheets. Compliance voltage is one specification that users consider when purchasing a potentiostat. Although it is tempting to think “the higher the better,” a high compliance voltage is not without its price. The higher the compliance voltage is, the more power that the potentiostat requires. Higher power means more complexity, more weight, and generally higher cost. The frugal electrochemist asks, “How much compliance voltage do I really need?”