g.GAMMAsys and g.EEGcap are high-performance active and passive electrode systems for non-invasive electrophysiological derivations such as EEG, EMG, ECG, EOG and other signals. Active electrodes have an additional ultra-low noise pre-amplifier located inside the electrode. The system is designed for use with g.USBamp, g.HIamp, g.BSamp and g.MOBIlab+. The actice electrodes work in a frequency range from 0 - 10 kHz (DC) or 0.1 Hz - 10 kHz (AC). The active and passive electrodes can be used with all g.tec EEG caps.

The system avoids or reduces artifacts and signal noise resulting from high impedance between the electrode(s) and the skin (e.g. 50/60 Hz coupling, artifacts caused by electrode or cable movements, distorted signals or background noise). 

g.tec provides various active and passive biosignal electrodes. Passive electrodes are equipped with a 1.5 mm DIN touch-proof safety connector and are plugged directly into the amplifier's input sockets or into an electrode connector box fitting to the amp. All active electrodes are equipped with 1 mm 2-pin touch-proof safety connectors and are plugged into g.GAMMAbox and g.SAHARAbox which is connected to the amplifier via an appropriate connector cable.

We use mainly high-purity gold (Au), chlorided silver (AgCl) and sintered Ag/AgCl electrode materials. Gold electrodes are very robust and easy to maintain and provide a very good signal quality at frequencies above 0.1 Hz (not suitable for DC recordings). AgCl and Ag/AgCl electrodes provide excellent signals, lowest polarization and drift and can be used for DC recordings if desired. We do not use other materials such as tin or stainless steel, as these materials may cause lower signal quality in terms of drift, polarization and noise.

We recommend using electrodes with gels, creams or pastes provided by g.tec. All our electrodes have been tested with these products. Other products can be used, of course, but highest performance cannot be guaranteed.