--Introduction--
1
Introduction
The Universal Dummy Cell 3 (UDC 32) is a printed circuit board used for calibration and troubleshooting of a
Gamry potentiostat. It has 3 “test cells”equipped with terminals, arranged around the boarders of the printed
circuit board.
The terminals are marked with labels corresponding to the leads on a Gamry Cell Cable. The FAS2 has fewer
cell leads than a PCI4 or Reference 600, so some terminals will have no connection to an FAS2.
This document applies to the UDC 3, engineered to work with Gamry’s PCI4 family of potentiostats and the
newer Reference 600 Potentiostat. The UDC3 is clearly labeled with the text “Universal Dummy Cell 3”
written diagonally across its printed circuit card.
AC calibration of a Reference 600 Potentiostat should always be done using a UDC3. Stray capacitance on an
older UDC2 will cause significant phase errors at 1 MHz.
Calibration
The calibration circuit is a 2 kprecision resistor (with some protection components). It is accurate to better
than 1 . Because potentiostats are not perfectly accurate, its value measured with a Gamry potentiostat is
typically between 1.994 kand 2.006 k.
Very early revision UDCs had a 100 resistor in the calibration circuit. PCI4 family potentiostats and the
Reference 600 require a 2 kresistor. 100 Universal Dummy Cells (shipped before May 2003) will not
calibrate a PCI4 family potentiostat or a Reference 600 to its full accuracy.
AC calibration of a Reference 600 Potentiostat should always be done using a UDC3. Stray capacitance on an
older UDC2 will cause significant phase errors at 1 MHz.
You can also use the calibration circuit to test for proper operation of your potentiostat. Use any technique.
The current at any potential should be given by Ohm’s law, I = E/R. At 1 Volt, the current should be 500 A.
More specifically, we recommend you use one of these techniques if you have concerns about your
potentiostat’s health:
DC105 Polarization Resistance
EIS300 Potentiostatic EIS
PHE200 Cyclic Voltammetry
EIS
The EIS Dummy Cell is a Randle’s cell (as described in Gamry’s Help system). If you have a license for
Gamry’s EIS300 Electrochemical Impedance Spectroscopy software, you can record this cell’s EIS spectrum to
check your system’s EIS operation.
Figure 1, a circuit diagram of the EIS cell is shown below. Figure 2 is a typical spectrum of the cell in Bode
format.
A visual examination of the spectrum is usually sufficient to determine if your EIS system is working. Most
system malfunctions totally prevent recording of the spectrum or cause gross errors that dramatically change the
shape of the curve.
