Gamry Reference 3000 - Input Impedance Selection

Appendix D -- Auxiliary A/D Input Characteristics--
14 - 2
Figure D-1
Auxiliary A/D Input Configuration Jumpers
View of Reference Family Controller Board
Input Impedance Selection
Two jumpers are associated with the input impedance – J902 and J903. With J902 and J903 installed, the Aux
A/D input has a 100 kΩ input impedance. This is the default setting. With the jumpers installed, the
potentiostat can be calibrated without a cable on the input BNC connector.
With both J902 and J903 removed, the Aux A/D input impedance is 10 GΩ (typically). This setting is suitable
for use with a high impedance source such as a reference electrode. If you have removed these jumpers, do
not calibrate the potentiostat unless you have a cable connecting both Aux A/D inputs to floating ground.
The CMOS switch shorts the circuit nodes connected by these jumpers. As with the jumpers, in the Low
Impedance setting, the input impedance is set to 100 kΩ. In the high impedance setting, the CMOS switches
are opened increasing the input impedance to about 10 GΩ.
Filter Jumper Input Z Jumpers