Instrument Circuitry – Reference 3000 Schematic/Block Diagrams
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Figure 3-4
Aux Channel Input Switching
Notes for Figure 3-4:
Two ADC Channels are dedicated to the potentiostat’s voltage and current signals. This diagram shows
the signals that can be connected to the third channel.
The Aux ADC BNC input is a differential input. Some of this input’s characteristics can be changed by
either jumpers or CMOS switches. Early Reference 3000’s use jumpers to change the characteristics,
while later units (shipped after the middle of 2009) use CMOS switches under software control to
change the characteristics. Contact Technical Support at Gamry.com if you are uncertain which type of
unit you have.
Jumper-configured Reference 3000s are shipped configured for input impedance of 100 k
and
unfiltered operation. The jumpers shown in this diagram allow it to be configured for high input
impedance or input filtering.
The thermocouple input allows for connection of a K-type thermocouple. Note that this circuit must
be calibrated to obtain reasonable accuracy. A section of the Reference 3000 calibration procedure
allows for user-calibration of this input.
The other two inputs to the Aux channel can be used to measure the AE (Auxiliary Electrometer) signal
or a Control Amp voltage signal.
