eDAQ e-corder, Manual

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Chapter 4 — The QuadStat 53
With Scope software, the corresponding controls are shown in Figure
4–10 .
Signal Display
The current signal is previewed scrolling across the display area. Note
that the signal is not being recorded to hard disk at this stage, and that
when the window is closed the signal trace is lost.
You can stop/start the signal scrolling by clicking the Pause/Resume
button .
You can shift or stretch the vertical Amplitude axis to make the best use
of the available display area. All changes to axis scaling are reflected
in the Chart and Scope main window, and vice versa.
Setting the Range
The Range pop-up menu lets you select the input current range or
sensitivity. The QuadStat has ranges of 20 pA to 10 mA. You should set
the range so that it is larger than the biggest current that you expect to
encounter during your experiment. If, during the experiment the current
signal exceeds the range, then the data will be truncated and therefore
lost.
Filtering
The QuadStat has low-pass filter settings (10 kHz to 1 Hz) for removal
of high frequency signals (‘noise’). The Off setting gives the full
bandwidth of the QuadStat which can be up to 16 kHz (but which may
also be limited by the characteristics of your electrodes and sample
solution). The more sensitive gain ranges will have a smaller maximum
bandwidth.
The 10 Hz (and smaller) filter settings, are highly effective for the
removal of mains hum (50 or 60 Hz interference) and, as a general
rule, should be employed whenever possible. However, low pass filters
should be used with care when performing pulse amperometric or
voltammetric experiments, or for other signals which are likely to exhibit
fast rise or fall times. For example, if you are using the 10 Hz filter, then
applied potential pulses should be longer than 100 ms, and scan rates