A-M Systems Microelectrode AC Amplifier Model 1800

A-M Systems

Microelectrode AC Amplifier Model 1800


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The Model 1800 Microelectrode AC Amplifier is a two-channel, differential amplifier designed for two headstage probes and is intended for extracellular recording and/or stimulating with high impedance metal microelectrodes in research and teaching applications. Extracellular neurophysiological recordings with high impedance microelectrodes can easily be done from excitable tissues such as nerve and muscle. The instrument is not intended for clinical measurements in human subjects.
Special Features
Mode Selection: This switch allows the user to select one of three Modes for each channel of the amplifier: Impedance Check (IMP), Record (REC), or Stimulate (STIM). During Impedance Check, an internal 1 kHz oscillator automatically applies a calibrated current through the electrode and the amplifier monitors the voltage in order to check impedance.
Capacity: This control is used to neutralize the capacitance during electrode impedance check. In record mode, the instrument amplifies the differential input signal by an amount selected by the Gain switch. In the Stimulate mode, a stimulus is applied directly to the electrode through the Stimulus connector, and the amplifier monitors the current passing throught the electrode.
Gain Selection: In the Record mode, the gain of each amplifier may be independently set by adjusting the Gain switch to x100, x1000, or x10,000.
The headstage for the Model 1800 is small and convenient. It is 0.535 inches (1.395 cm) in diameter and 4 inches (10.2 cm) long. It includes a 0.187 inch (4.7 mm) diameter mounting rod and 5 feet (1.5 m) of Superflex silicone jacketed cable which resists mild alkalis, acids and solvents. It has 0.062 inch female pin connectors to attach to your sensors.


  • Amplifier for metal microelectrodes
  • Two amplifiers in one instrument
  • Recording gain options: x100, x1000, x10 000
  • Low noise (1.0 µV p-p typical, 10 Hz–10 kHz)
  • High common-mode rejection ratio (100 dB at 60 Hz)
  • High line frequency rejection with notch filter (>110 dB at 60 Hz) (50 Hz notch filter optional)
  • High input impedance (100 000 MΩ)
  • Low input bias current (±3 pA typical; ±20 pA maximum)
  • Adjustable low and high frequency filters
  • Power supply may be set for 110 VAC at 60 Hz or 220 VAC at 50 Hz