ActiveThree: Smaller, lighter, and faster active electrode EEG 

Biosemi introduces their third generation active electrode biopotential measurement system for electrophysiological research - ActiveThree. This new system expands on decades of design leadership in the field and continues to incorporate active electrodes with a preamplifier integrated in the electrode, a compact battery powered AD-box, and data transfer to the acquisition computer via a single optical fiber. This setup offers optimal interference reduction and safety, and Biosemi’s systems have become the de facto standard workhorse for electrophysiological research with more than 2000 systems in use and over 10,000 scientific publications. However, recent advances in semiconductor and battery technology create an opportunity to develop a significantly improved successor.

By placing active electronics within millimeters of the actual electrode contact, ActiveThree virtually eliminates the need to prepare the scalp before applying electrodes. This can cut measurement preparation time by half or more compared to passive systems while also increasing signal quality!

ActiveThree can also be equipped with additional sensors for respiration, skin conductance, temperature, plethysmograph (pulse) and other parameters.

ActiveThree comes with free, robust, and intuitive data acquisition software called ActiView.

Each ActiveThree system is built upon a basic set of items known as the Base System.

ActiveThree Base Components (part of every new system)

  • CMS/DRL input, touchproof (electrodes sold separately)
  • 3 x standard battery cell type 18650. 3 Volt Lithium-Ion
  • Lithium-Ion charger for 18650 type batteries
  • 10 meter optical fiber, SC-SC style connectors. 62.5-125 uM
  • Optical receiver / USB 2.0 interface with trigger in/out connector (16 digital in, 12 digital out)
  • USB 2.0 cables type A and C (1.8 meter)
  • Carrying case
  • Cable rack (to mount on wall for electrode storage)
  • ActiView data acquisition software
  • DA-A3-BCBS3

    ActiveThree BASE USA (channel modules, sensors, and electrodes sold separat

  • DA-A3-BCADB3

    ActiveThree AD-box (USB interface, cables, channel modules, sensors, and el

  • DA-A3-BCAC3

    Amplifier Module for ActiveThree (8 channels)


    ActiveTwo/Three USB 2.0 interface with USB cable and software driver


    ActiveTwo USB virtual serial port trigger cable

Typical Additional Components

  • Amplifier/Converter modules – add up to 17 8-channel modules per A/D interface box
  • Multichannel active electrode sets are available with a variety of labeling schemes
  • Head Caps – Multiple sizes are needed to cover a range of head sizes
  • Flat-type active electrodes with individual leads and touch-proof connectors for EEG reference, EOG, EKG, and surface EMG
  • CMS/DRL electrodes serve as the common for every biopotential measurement, and for EEG measurements with the cap, you will need one set of pin-type CMS/DRL electrodes, and for measurements not using a head cap, a flat-type CMS/DRL is needed

Other Optional Components

  • Auditory brainstem response module
  • Optional sensors for galvanic skin response, respiration, temperature, or pulse/plethysmograph
  • Ergo input and for use with battery-powered or self-powered signal sources such as a condenser microphone or a photocell and Ergo-optical adapter for unisolated signal sources, such as audio
  • Additional head-caps in various sizes with the same layout as the primary caps, or in different layouts