Zra-Mode Cell Connections - Gamry Instruments Interface 1000 Operator's Manual

If your cell is a typical glass laboratory cell, all of the electrodes are isolated from earth ground. In this case, you
may be able to lower noise in your data by connecting the Interface 1000's Chassis Ground to an earth
ground.
Caution: If any electrode in your cell is at earth ground, never connect the Interface 1000
chassis to earth ground. Autoclaves, stress apparatus, and field measurements may involve earth-grounded
electrodes. A binding post on the rear panel of the Interface 1000 is provided for this purpose. A water
pipe can be a suitable earth ground.
Warning: Make sure that your earth-ground connection is made to a legitimate source of
earth ground. Consult a qualified electrician if you are uncertain how to obtain an earth ground.
Connecting the Interface 1000 to an incorrect and unsafe voltage can create a safety hazard (see Chapter 1
for details).
If you are measuring very small currents, you may find that a metal enclosure completely surrounding your cell
(a "Faraday shield") significantly lowers measured current noise. Normally you connect this Faraday shield to
both earth ground and floating ground. The floating ground on the black cell lead is a convenient source of
ground.
If any electrode in your cell is connected to earth ground, only connect your Faraday shield to the black cell
lead (Chassis Ground).
You can remove the alligator clip on any cell connection to gain access to the underlying banana plug or pin
jack. Gamry Instruments also can provide additional standard or special cell cables.
In either potentiostatic or galvanostatic mode, if you do not have a reference electrode in your cell, the
reference lead can be connected to the counter electrode for a two-electrode experiment. The potential
reading then is the difference between the counter electrode and the working electrode.

ZRA-Mode Cell Connections

The Interface 1000 can function as a precision Zero-Resistance Ammeter (ZRA). It maintains two metal samples
at the same potential and measures the current flow between the samples. It can also measure the potential of
the samples versus a reference electrode.
The cell cable connections for ZRA mode are shown in Table 4-2. The connections are very similar to those for
the potentiostat and galvanostat modes. A second working electrode is substituted for the counter electrode
and the Orange Counter Sense lead must be connected.
Chapter 4: Cell Connections--ZRA-Mode Cell Connections
4 - 2