Voltage definition

Ideally a standard cell is constmcted simply and is characterized by a high constancy of emf, a low temperature coefficient of emf, and an emf close to one volt. The Weston cell, which uses a standard cadmium sulfate electrolyte and electrodes of cadmium amalgam and a paste of mercury and mercurous sulfate, essentially meets these conditions. The voltage of the cell is 1.0183 V at 20°C. The a-c Josephson effect, which relates the frequency of a superconducting oscillator to the potential difference between two superconducting components, is used by NIST to maintain the unit of emf. The definition of the volt, however, remains as the Q/A derivation described. 

Electrochemical cells may be used in either active or passive modes, depending on whether or not a signal, typically a current or voltage, must be actively appHed to the cell in order to evoke an analytically usehil response. Electroanalytical techniques have also been divided into two broad categories, static and dynamic, depending on whether or not current dows in the external circuit (1). In the static case, the system is assumed to be at equilibrium. The term dynamic indicates that the system has been disturbed and is not at equilibrium when the measurement is made. These definitions are often inappropriate because active measurements can be made that hardly disturb the system and passive measurements can be made on systems that are far from equilibrium. The terms static and dynamic also imply some sort of artificial time constraints on the measurement. Active and passive are terms that nonelectrochemists seem to understand more readily than static and dynamic. 

Switches and switch isolators for voltages above lOOOV General and definitions 9920-1 10 4/1992 BSEN 60265 1/1998 ... 

Voltage ratings for a.c. electrical systems and equipment above 230 kV Insulation coordination, definitions, principles and rules... 

High voltage test techniques - General definitions and test requirement 2071-1/199.3 BS 92.3-1/1990... 

F. Analysis for ozone. The analysis is made by passing a definite amount of oxygen through the ozonizer at a selected secondary voltage and then through a neutral 5% solution of potassium iodide. Iodine is liberated,... 

If an adjustable T-R is connected as forced stray current drainage between pipeline and rails and its output voltage is fixed at a definite level, the protection current and the pipe/soil potential can undergo considerable fluctuation. 

This is the simplest of all relay operating principles. Any current above, or voltage below, a set level may be taken to mean that a fault or some other abnormal condition exists inside the zone of protection. Figure 2 shows a definite time and an inverse time overcurrent relay. 

Variance, analysis, 277, 283-288 definition and equation, 268, 269 Voltage, adjustment, use in avoidance of line interference, 149 minimum desirable for excitation, 102... 

This pardaxin model is not unique. We have developed several similar models that are equally good energetically and equally consistent with present experimental results. It is difficult to select among these models because the helices can be packed a number of ways and the C-terminus appears very flexible. Our energy calculations are far from definitive because they do not include lipid, water, ions, membrane voltage, or entropy and because every conformational possibility has not been explored. The model presented here is intended to illustrate the general folding pattern of a family of pardaxin models in which the monomers are antiparallel and to demonstrate that these models are feasible. 

There are several major classes of Ca channels (1) receptor-operated Ca channels in plasma membranes (2) ligand-gated Ca " channels in intracellular membranes and (3) voltage-dependent Ca channels that are usually found in plasma membranes or the invaginations of the plasma membrane that are known as transverse tubule membranes. Receptor-dependent or receptor-operated Ca channels (ROCCs) are primarily opened in response to activation of their associated receptors and, by definition, exhibit a certain amount of selectivity for Ca " over other cations. Several potentially different types of ROCCs have been characterized including ATP-sensitive channels in smooth muscle [1], mitogen and IP3-sensitive... 

A definite decomposition voltage occurs for the following reason. As soon as there is a potential difference between the electrodes, H+ ions move to the cathode and Cl ions to the anode. The ions are discharged, forming layers of adsorbed gas on the inert metal surfaces. This essentially amounts to having a hydrogen electrode and a chlorine electrode in place of the two platinum electrodes. The outcome is a typical chemical cell ... 

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