eDAQ Picostat, User Manual

Page: 85 / 122

Chapter 5 — Techniques 81
cable will be carrying the potential signal (which will now appear on
Channel 1) and the ‘E Out’ cable the current signal (which will now
appear on Channel 2). When you start to record data you will find that
the Units Conversion on Channel 2 has been set to appropriate value
so that the signal is automatically displayed with the correct current
units.
The default setting is to have the applied current on the 100 mA range.
It is likely that there will be a small residual offset at this setting which
will cause the Potentiostat/ Galvanostat to go off scale (over 10 V) in
Standby mode (as it is connected to the relatively low resistance 10
5
Ω
internal dummy cell). Try selecting a more appropriate 1 µA or 10 µA
range, where the offset will be correspondingly smaller, and the signal
should come on screen and be close to zero volts.
The e-corder Output Voltage can be set as described earlier, Figure
5–8, on page 68 . At each of these Output Voltage range settings the
Potentiostat offers four current range settings when in Galvanostat
mode,
Table 5–1 . The most accurate control is achieved by using the
largest possible Output Voltage range with the smallest possible
Galvanostat range setting.
Adjust the current within the selected range. The resulting potential
signal is shown in the display area.
Galvanostat Current Ranges
e-corder Output
Range
Potentiostat/Galvanostat primary gain
100 nA/V 1 µA/V 10 µA/V 100 µA/V 1 mA/V 10 mA/V
10 V 1 µA 10 µA 100 µA 1 mA 10 mA 100 mA
5 V 500 nA 5 µA 50 µA 500 µA 5 mA 50 mA
2 V 200 nA 2 µA 20 µA 200 µA 2 mA 20 mA
1 V 100 nA 1 µA * 10 µA * 100 µA * 1 mA * 10 mA *
500 mV 50 nA 500 nA * 5 µA * 50 µA * 500 µA * 5 mA *
200 mV 20 nA 200 nA * 2 µA * 20 µA * 200 µA * 2 mA *
*
Usually it is better to use the corresponding setting elsewhere in the table.
Table 5–1
Galvanostat current
range settings of the
Potentiostat as a function
of
e-corder output range.