title: A simple and reproducible capacitive electrode.
abstract: Capacitive Electrodes (CE) allow the acquisition of biopotentials through a dielectric layer, without the use of electrolytes, just by placing them on skin or clothing, but demands front-ends with ultra-high input impedances. This must be achieved while providing a path for bias currents, calling for ultra-high value resistors and special components and construction techniques. A simple CE that uses bootstrap techniques to avoid ultra-high value components and special materials is proposed. When electrodes are placed on the skin; that is, with coupling capacitances C(S) of around 100 pF, they present a noise level of 3.3 µV(RMS) in a 0.5-100 Hz bandwidth, which is appropriate for electrocardiography (ECG) measurements. Construction details of the CE and the complete circuit, including a fast recovery feature, are presented.
authors.affiliation: LEICI - Departamento de Electrotecnia, Universidad Nacional de La Plata, CC 91 (1900) La Plata, Argentina; Consejo de Investigaciones Científicas y Técnicas (CONICET), Argentina . Electronic address: spinelli@ing.unlp.edu.ar.
authors.forename: Enrique
authors.initials: E
authors.lastname: Spinelli
authors.affiliation: LEICI - Departamento de Electrotecnia, Universidad Nacional de La Plata, CC 91 (1900) La Plata, Argentina; Consejo de Investigaciones Científicas y Técnicas (CONICET), Argentina.
authors.forename: Federico
authors.initials: F
authors.lastname: Guerrero
authors.affiliation: LEICI - Departamento de Electrotecnia, Universidad Nacional de La Plata, CC 91 (1900) La Plata, Argentina.
authors.forename: Pablo
authors.initials: P
authors.lastname: García
authors.affiliation: LEICI - Departamento de Electrotecnia, Universidad Nacional de La Plata, CC 91 (1900) La Plata, Argentina; Consejo de Investigaciones Científicas y Técnicas (CONICET), Argentina.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Haberman
mesh_terms: D025802:Electric Capacitance; D017097:Electric Impedance; D004562:Electrocardiography / Q000295:instrumentation; D004566:Electrodes; D015203:Reproducibility of Results
keywords: Active electrodes; Insulating electrodes; Non-contact measurements