The GSR100C measures both the skin conductance level (SCL) and skin conductance response (SCR) as they vary with sweat gland (eccrine) activity due to stress, arousal or emotional excitement. The GSR100C uses a constant voltage (0.5 V) technique to measure skin conductance. The controls allow selection of absolute (SCL+SCR) or relative (SCR) skin conductance measurements.
AcqKnowledge includes a fully automated electrodermal response scoring tool that locates skin conductance responses, visually identifies them in the record and measures them. It also automates event related potentials (ERP) analysis by locating the onset of the stimuli and identifying a valid SCR. See the Applications > Psychophysiology Area for further information.
Each GSR100C amplifier requires one set of the following electrode combinations:
2 x LEAD110A Electrode Leads (Recommended)
2 x EL507 Disposable Electrodermal Electrodes (Recommended)
When using the EL507 wait 5 minutes (minumum) before starting to record data. When using GEL101 it is important that the gel has a chance to be absorbed and make good contact before recording begins. Accordingly:
Apply GEL101 to the skin at the point of electrode contact and rub it in.
Fill the TSD203 electrode cavity with GEL101.
Attach the TSD203 electrode to the subject.
Wait 5 minutes (minimum) before starting to record data.
Calibration To set up AcqKnowledge to record skin conductance directly, perform the following:
Lower frequency response at DC
In the scaling window, set the input voltages so they map to the DC conductance ranges indicated by the sensitivity setting. For example, if the GSR100C is set to a Gain of 5 µmho/V, then 0V will map to 0 µmhos or infinite resistance and 1V will map to 5µmho or 200kohm.
Lower frequency response at 0.05 Hz
In the scaling window, set the input voltages so they map to the 0.05Hz conductance ranges indicated by the sensitivity setting. For example if the GSR100C is set to a Gain of 5 µmho/V, then 0V will map to X µmhos and 1 V will map to (X+5) µmhos, where X is the mean conductance being recorded.
To verify the Gain setting of the GSR100C:
Calibrate AcqKnowledge as detailed above for lower frequency response at DC.
Place the lower frequency response to DC.
Set the Gain switch on the GSR100C to 5 µmho/V.
Perform measurement with electrodes disconnected.
AcqKnowledge should produce a reading of 0 µmho.
Insulate a 100 kohm resistor and place it from electrode pad to electrode pad (resistor must be insulated from fingers.
Perform measurement with electrode-resistor setup.
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