Ammeter portable hand-held clamp-on ammeter is a common tool for maintenance of industrial and commercial electrical equipment, which is temporarily clipped over a wire to measure current. Some recent types have a parallel pair of magnetically soft probes that are placed on either side of the conductor. Ammeter An ammeter (from Ampere Meter) is a measuring instrument used to measure the current in a circuit. Electric currents are measured in amperes (A), hence the name. Instruments used to measure smaller currents, in the milliampere or microampere range, are designated as "milliammeters" or "microammeters". Early ammeters were laboratory instruments which relied on
Coal Measures Group the: In South Wales, the larger part of what had been the Upper Coal Measures now forms the Pennant Sandstone Formation in the overlying Warwickshire Group. The South Wales Coal Measures Group is preceded (underlain) by the Marros Group. Coal Measures Group The Coal Measures Group is a lithostratigraphical term coined to refer to the coal-bearing succession of rock strata which occur in the United Kingdom within the Westphalian Stage of the Carboniferous Period. Other than in Northern Ireland the term is now obsolete in formal use and is replaced by the Pennine Coal Measures Group, Scottish Coal Measures Group