GSR Amp
The FE116 GSR Amp is a galvanically isolated, skin conductance response amplifier with low constant-voltage AC excitation and automatic zeroing. The low level AC excitation reduces electrode polarization artifacts found in DC systems. The GSR Amp is galvanically isolated for subject safety and approved to the IEC601‑1 standard for human connection as a body protected (BF rated) instrument. It is supplied with a pair of MLT116F finger electrodes with Velcro™ attachment straps.
Features
- 75 Hz oscillator which supplies a near square wave, low-impedance, low-voltage (22 mVrms) signal to an electrode on one finger of the subject.
- Galvanic isolation for subject safety and approval to the IEC60601-1 standard for human connection as a body protected (BF rated) instrument.
- Automatic zeroing
- Supplied with GSR Finger Electrodes and adult Velcro® straps
Compatibility
The GSR Amp is compatible with all PowerLab and MacLab models and requires the following ADInstruments software versions or later: LabChart v6, Chart v4 or Scope v3.5.
Visit www.adinstruments.com/downloads/ for Windows and Mac operating system compatibility. For more information please contact your ADInstruments representative.
Operation
The 75 Hz oscillator supplies a near square wave, low-impedance, low-voltage (22 mVrms) signal to an electrode on one finger of the subject. If the skin has a measurable conductance, current flows from the electrode on the other finger back into the very low impedance input of the transimpedance amplifier. The current is then converted to a voltage signal. The current will change as the autonomic reflexes change the skin's conductivity.
- Do not use recording gel with the electrodes. This will tend to give higher basal readings as skin resistance is lowered by gel.
- Avoid measuring skin conductance if the subject is perspiring excessively at rest.
Applications
The FE116 GSR Amp is used to measure the Féré effect, a general measurement of autonomic nervous system activity. It can be used to analyze the startle response to visual, auditory or somatosensory stimuli.
Input
- Connection type: 2 × 4 mm shrouded sockets. Custom cable with two dry,
bright-plated, bipolar electrodes with Velcro™ attachment
strap suitable for adult fingers. - Excitation: Constant-voltage AC excitation(22 mVrms @75 Hz)
- Current density: ≤0.5 μA cm–2
- Safety: Approved to IEC601-1 BF (body protection) standard
- Configuration: Transformer isolation (AC bridge operation)
- Isolation rating: 4000 V ACrms for 1 minute
- Input ranges: 1 to 40 μS full scale in 6 steps (combined PowerLab and GSR Amp)
- 0 to 40 μS
- 0 to 20 μS
- 0 to 10 μS
- 0 to 4 μS
- 0 to 2 μS
- 0 to 1 μS - Frequency response: –3 dB at 1 Hz
- Accuracy: ±5 %
- Input leakage current: <3 μArms at 240V, 50 Hz; <2 μArms at 120V, 60 Hz
- Zeroing and offset: Automatic software-controlled fast zeroing, controlled by internal 12-bit DAC; resolution = ±0.2 μS
Output
- Analog signal: ±2 V full scale
Control port
- I2C port: Provides control and power. Interface communications rate
of ~50 Kbits/s.
Physical configuration
- Dimensions (h × w × d): 55 mm × 120 mm × 260 mm
- Weight: 1.2 kg
- Power requirements: 2.5 W maximum
- Operating temperature range: 0 to 35 °C, 0 to 90% humidity (non-condensing)
ADInstruments reserves the right to alter these specifications at any time.
- MLT118F GSR Finger Electrodes (Snap Lead) with Velcro® straps suitable for adults