10-61
screen. The ratio of the average current during the time interval just passed to that of
the first time interval is also shown. This ratio is an important criterion for
determining the extent of the electrolysis; that is, electrolysis is generally complete
when this ratio reaches 1% (any residual current being background current). This
End Current Ratio can be set by the user (1% is the default value). In addition to
numerical results (see below), the experimental data can be presented by a charge vs.
time plot (Figure 10-40) or a current vs. time plot (Figure 10-41).
Figure 10-40. Typical charge vs. time plot for BE.
Figure 10-41. Typical current vs. time plot for BE.
The total charge is measured by taking successive readings from the I-E converter
and adding these values together. Although this simplifies the measurement, some
charge is invariably lost. The error depends on the timescale of the BE experiment.
At very short time (less than 0.1 sec), the error is typically 1-5%; however, at 10
seconds, the error is only about 0.03 to 0.05%. As the timescale of BE experiments is
typically of the order of minutes, the charge loss due to the simplified measurement
technique is generally negligible.
