Wait until the Status Display shows that the frequency is below 2 kHz. Click the Curve List. Move down the list and examine the display for each selection.
|ZCURVE||The EIS spectrum being acquired as a Bode plot (magnitude and phase vs. frequency).|
The open-circuit voltage vs. time curve recorded prior to the frequency sweep.
|FRACURVE||The current-versus potential-curve (Lissajous figure) recorded at the current frequency.|
The EIS spectrum being acquired as a Nyquist plot (real vs. imaginary)
|ACTIVE||The last display that has been changed.|
Notice that the FRACURVE is constantly changing as new A/D-converter values are taken. The FRACURVE is shown even for points acquired using an external analyzer. The external analyzer applies a sine wave and the potentiostat's internal A/D converter is used to measure both E and I. In this case, the A/D converter's values are used to determine the DC values required for intelligent autorange decisions. The actual impedance is measured in the external analyzer.
By default, the Curve List selection is set to ACTIVE. In the ACTIVE setting, the displayed curve is changed whenever information is written to a curve different from the curve that is currently displayed. In practice, the EIS software most often displays the FRACURVE. After each point is acquired, the ZCURVE is shown momentarily, but is quickly replaced with a FRACURVE from the next frequency.
Continue the tutorial.