Electrical contacts Electrical contacts An electrical contact is an electrical circuit component found in electrical switches, relays, connectors and circuit breakers. Each contact is a piece of electrically conductive material, usually metal. When a pair of contacts touch, they can pass an electrical current with a certain contact resistance, dependent on surface structure, surface chemistry and contact time; when the pair is separated by an insulating gap, then the pair does not pass a current. When the contacts touch, the switch is "closed"; when the contacts are separated, the switch is "open". The gap must be an insulating medium such as air,
Electrical cardiometry Electrical cardiometry Electrical cardiometry is a method based on the model of "Electrical Velocimetry", and non-invasively measures stroke volume (SV), cardiac output (CO), and other hemodynamic parameters through the use of 4 surface ECG electrodes. Electrical cardiometry is a method trademarked by Cardiotronic, Inc., and is U.S. FDA approved for use on adults, children, and neonates. The measured bioimpedance over time can be expressed as the superposition of three components: where Z is the quasi-static portion of the electrical impedance (base impedance), ΔZ are the changes of impedance due to the respiratory cycle, and ΔZ are the changes of impedance