Related Experiment Video
Updated: Mar 26, 2026

Author Spotlight: Microfluidic Channel-Based Soft Electrodes and Their Application in Capacitive Pressure Sensing
Published on: March 17, 2023
A simple and reproducible capacitive electrode
Enrique Spinelli1, Federico Guerrero2, Pablo García3
1LEICI - Departamento de Electrotecnia, Universidad Nacional de La Plata, CC 91 (1900) La Plata, Argentina; Consejo de Investigaciones Científicas y Técnicas (CONICET), Argentina .
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.
Related Concept Videos
Dielectric Polarization in a Capacitor
Capacitor With A Dielectric
Dielectrics are non-conducting materials with no free or loosely bound electrons. When a dielectric is...
Potentiometry: Types of Electrodes
The Standard Hydrogen Electrode (SHE) is a widely used reference electrode that maintains zero potential across all temperatures. However, its need for a continuous hydrogen gas supply renders it impractical for everyday use.
An alternative to SHE is the Saturated Calomel Electrode (SCE). This electrode features an...
Design Example: Resistive Touchscreen
When a user touches the screen, the two layers make contact at a specific point known as the touchpoint. This contact reduces the resistance between...
MOS Capacitor
The metal gate is typically made from highly conductive materials such as aluminum or polysilicon. Beneath the metal gate lies a thin layer of...
Equivalent Capacitance
The following strategies are adopted to calculate...

