Ammeter Wattmeter for an alternative use for this instrument. Moving iron ammeters use a piece of iron which moves when acted upon by the electromagnetic force of a fixed coil of wire. The moving-iron meter was invented by Austrian engineer Friedrich Drexler in 1884. This type of meter responds to both direct and alternating currents (as opposed to the moving-coil ammeter, which works on direct current only). The iron element consists of a moving vane attached to a pointer, and a fixed vane, surrounded by a coil. As alternating or direct current flows through the coil and induces a magnetic field
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