par Cerf, Jean ;Libert, Charles
Référence Electroencephalography and clinical neurophysiology, 12, 2, page (510-513)
Publication Publié, 1960-05
Article révisé par les pairs
Résumé : The paper describes a preamplifier (A) designed for intracellular or extracellular recordings of bioelectric potentials with high resistance microelectrodes. The high-impedance input stage uses a subminiature penthode, and can be switched from a conventional cathode-follower circuit (for extracellular recording) to an "inverted triode" electrometer type circuit (for intracellular recording). Two following stages equipped with low-noise transistors provide a high overall gain (800 × for extracellular and 35 × for intracellular recordings), sufficient for driving any low-gain C-R oscilloscope without additional amplification. When recording intracellularly, stray input capacity and capacity to ground of the microelectrode are neutralized by negative capacitance adjustable by positive feedback, thus improving transient response. Table I summarizes the operating characteristics of the circuit. A calibrating device (B) can be used in conjunction with the preamplifier. © 1960.