Cryogenic Current Comparator
The cryogenic current comparator (CCC) is used in the electrical precision measurements to compare electric currents with the highest accuracy. This device exceeds the accuracy of other current comparators around several orders of magnitude. It is used in electrical metrology for exact comparative measurements of electrical resistance, electric resistances or the amplification and measurement of extremely small electric currents. The CCC principle goes back on ''Harvey'' and is based substantially on the properties of superconductivity, superconductors. CCCs make use of macroscopic quantum effects that occur in superconducting materials or circuits underneath their critical temperature of typically a few kelvins. The term "Cryogenic Current Comparator" stems from ''κρυος'' (Greek language, Gr. ''frost'', ''ice'') and ''comparare'' (Latin language, Lat. ''compare''). The two quantum effects used in a CCC are the ideal diamagnetism of the superconductor, caused by the Meissner eff ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Electric Current
An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes. In an electrolyte the charge carriers are ions, while in plasma, an ionized gas, they are ions and electrons. The SI unit of electric current is the ampere, or ''amp'', which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit. Electric current is measured using a device called an ammeter. Electric currents create magnetic fields, which are used in motors, generators, inductors, and transformers. In ordinary con ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]