Amperes

In this case the only variation is the magnetization power, measured in Ampere Turn. 

An eunmeter, reading to 1 5-2 0 amperes, sho dd be placed in the circuit, t Supplied by Zenith Electric Ltd. j Supplied by Sunvic Controla Ltd. 

Electrolysis cell. This is shown in Fig. VI, 31, 1 and is almost self-explanatory. The cylindrical cell of Pyrex glass (6" long by 2 " diameter) is cooled by immersion in a cooling bath. The electrodes consist of two platinum plates (4 cm. X 2-5 cm. X 0-3 mm.), which are placed about 2 mm. apart. The temperature of the electrolyte is maintained at 30-35° by means of the internal cooling coil and also by immersion of the cell in ice-water. A current of 1 5-2 0 amperes is passed until the electrolyte becomes slightly alkaline, which normally takes about 20-50 per cent, longer than the calculated time on the basis of the current and the amounts of acid employed. It is advantageous to reverse the direction of the current occasionally. 

Electric current ampere A Magnitude of the current that, when flowing through each of two straight parallel conductors of infinite length, of negligible cross-section, separated by 1 meter in a vacuum, results in a force between the two wires of 2 X 10 newton per meter of length. 

Ampere per square centimeter ampere per square inch 6.4516... 

Ampere-turn per centimeter ampere-turn per inch 2.540... 

In potentiometry, the potential of an electrochemical cell under static conditions is used to determine an analyte s concentration. As seen in the preceding section, potentiometry is an important and frequently used quantitative method of analysis. Dynamic electrochemical methods, such as coulometry, voltammetry, and amper-ometry, in which current passes through the electrochemical cell, also are important analytical techniques. In this section we consider coulometric methods of analysis. Voltammetry and amperometry are covered in Section 1 ID. 

By contrast, in SI units, the coulomb (C) is the unit of charge and is defined as an ampere second (A sec). To reconcile this with newtons and meters, the units of F and r, respectively, a proportionality constant that is numerically different from unity and which has definite units is required. For charges under vacuum we write... 

American Gas Association ampere hour American Institute of Chemical Engineers American Institute of Mining, Metallurgical, and Petroleum Engineers... 

Fig. 10. Power factor at 1 MHz vs temperature for some commercial glasses. Courtesy of Corning Inc. The power factor is the ratio of the power ia watts dissipated ia a material to the product of the effective siausoidal voltage and current ia volt-amperes. When the dissipation factor is less than 0.1, the power...

Because of the very large resistance of the glass membrane in a conventional pH electrode, an input amplifier of high impedance (usually 10 —10 Q) is required to avoid errors in the pH (or mV) readings. Most pH meters have field-effect transistor amplifiers that typically exhibit bias currents of only a pico-ampere (10 ampere), which, for an electrode resistance of 100 MQ, results in an emf error of only 0.1 mV (0.002 pH unit). 

Resistivity/Conductivity. The resistivity or specific resistance of a material is the electric resistance offered by an element of the material having unit length and unit cross-sectional area. The current iatensity is proportional to the voltage across its path, and is iaversely proportional to resistance. This relationship is expressed by Ohm s law, where I = current ia amperes, E = poteatial ia volts, and R = resistance ia ohms. 

GMR dramatically en-hanced by presence of the thin Cu layer mag-netoresistance of more than 17% for field changes of 8 kA/ m at room temperature resistance changes as large as 70% within a few tens of amperes per meter... 

P. J. Kanyha and S. Brey, 22nd Congr. AMPERE Magn. Reson. Relat. Phenom. Proc., 341 (1984). 

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