There must be good electrical connections between the skin and the electrodes for EDA to work properly. When using GEL101 it is important that the gel has a chance to be absorbed and make good contact before recording begins. Accordingly:
- Fill the TSD203 electrode cavity with GEL101.
- Attach the TSD203 electrode to the subject.
- Wait 5 minutes (minimum) before starting to record data.
To verify the Gain setting of the EDA100C:
- Calibrate AcqKnowledge for 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 EDA100C is set to a Gain of 5 µmho/V, then 0 V will map to 0 µmhos or infinite resistance and 1 V will map to 5 µmho.
- Place the lower frequency response to DC.
- Set the Gain switch on the EDA100C 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.
Acq Knowledge should produce a reading of 10 µmho.
- Disposable option: EL507 Disposable EDA electrode with LEAD110A Electrode Lead
- BioNomadix wireless option: BN-EDA-LEAD2 with BN-PPGED
BIOPAC software calculates conductance in µMho, the traditional unit of conductance. Micromho (µMho) is interchangeable with the alternative microsiemen (µS). To use Ohm, the traditional measure of resistance, convert as 1 µMhos equals 1,000,000 ohms.