[en] Electricity is a form of energy that with its applications and multiple developments, it has changed considerably the modern life. As source of energy has been fundamental to satisfy basic needs of the humanity, and in some instances it has generated new relative services to the technological advance. Its intense use is present in fields as the lighting and heating, the motor force, transportation, communications, the processing, storage and multiplication of the information, the medicine and the recreation; its supply has been converted an essential service for the development and progress of the society

[en] The year marking the beginning of atmospheric electricity as a branch of the atmospheric sciences can be pinned down with unusual accuracy. In 1752 the two pertinent facts are ascertained: that the phenomena typical of thunderstorms are of the same nature as those of artificial electricity (as generated in the laboratory), as Dalibard demonstrated with an experiment suggested a little earlier by Benjamin Franklin, and secondly, that fair weather air is electrified, which was Lemonnier's no less significant discovery in that very year. To recall some events surrounding these discoveries, bracketed by former speculations and some later developments, is the aim of this paper

[en] A brief summary is presented on the evolution of electricity knowledge from antiquity to our days. At the same time the growth of its practical applications, i. e. the electrical industry, is described, as well as its technical, scientific, economic and social consequences

[en] This article focuses on the use of mathematical modeling for the calculation of electrical circuits. The Mat Lab software package is selected. A method has been developed for calculating complex electrical circuits by solving systems of linear algebraic equations using the matrix method. An example of the calculation in the Mat Lab package of the currents of the branches and node potentials of an electrical circuit is given. The conclusion was made about the universality of the use of mathematical modeling in technical calculations. (author)

[en] Operation of electric measuring instrument covering electric current and electric potential measuring instruments, multimeter, shunt Ohm meter and Watt meter are discussed. (SMN)

[en] This article presents statistics on accidents involving electricity for the period 1992 to 2001 in Switzerland and discusses their use as a means of accident prevention. The statistics, which cover those accidents occurring to professional electricians and in trade and industry are presented in tabular and graphical form. Accidents to non-professionals are complete as far as fatal accidents are concerned. Examples of accidents are given, such as ones caused by not checking that components were free of voltage, mix-up of cables, short-circuits on bus bars, missing fault-current detection and unsatisfactory supervision of apprentices. The causes of the accidents are examined and commented on. Suggestions are made on how such incidents can be prevented

[en] In this work a review is made of important concepts in the study of the transport of electric charge in insulators. These concepts are: electrical contacts, transport regimes as viewed in the I-V characteristics, and photoinjection processes by internal photemission of holes or electrons from metals or semiconductors into insulators or by a virtual electrode using strongly absorbed light. Experimental results of photoinjection of holes and electrons into sulfur single crystals are analyzed using these concepts. The observation of the Mott-Gurney transition is reported for the first time. This is the transition between the region of space charge limited currents (SCLC) and the region of saturation of the current as a function of the applied voltage. A modified Mott-Gurney theoretical model is presented that is able to explain the whole I-V characteristic for uv and the internal photoemission of hopes and uv photoinjection of electrons. For the case of internal photoemission of electrons the conventional space charge limited current theory for an exponential distribution of traps is able to explain the experimental data. It is found that the crystals are of high purity since the total density of traps, as calculated from their exponential distribution, is Nsub(t) equals 1.8 X 10¹⁴cm^-3. (author)

[en] In this work is given a full theoretically treatment of the problem how to determine the critical density of charge on nonconductive rectangular charged surfaces placed near a small spherical conductive and earthed surface. (author). 11 refs, 2 figs

[en] In this work we give a full theoretical treatment of the problem of how to determine the electric fields between non conductive rectangular charged surface placed near a small spherical conductive earthed surface, and of critical density of charge. (author). 10 refs, 2 figs

[en] The electromagnetic field for a thin wire of finite length, embedded in a homogeneous earth of infinite extent in all directions, is given. The distribution of the electric field intensity close to the wire is examined. The mathematical model for the finite wire is expanded by substituting a spheroidal earth-electrode at each end. The external self-impedance of the wire between the earth-electrodes is calculated by integrating the electric field intensity along a presupposed radius. Especially in the case of short wires the results show considerable deviations to the known depth of current penetration as compared to that of an infinitely long wire. By considering the approximations used for short wires in this model, one can draw conclusions on the external self-impedance for short wires above, on and under the earth's surface. (orig.)