Electricity in Theory and Practice: Or, The Elements of Electrical EngineeringD. Van Nostrand Company, 1883 - 270 pages |
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absorbed per 1,000 action alternating currents amount ampères angle Approximate rise armature attraction brushes carbon cell centimetre charge coarse coils coils conductor connected copper core cuit cylinder decrease deflection devices difference of potential discs distance ductor dynamo earth Edison effect elec electric current electrical efficiency electro-magnet electro-motive force electrode electrolytic energy equal ergs farad field-magnet coils galvanometer glass gramme greater heat horse-power increase induced inductive effect insulating lamp lead lines of force machine magnet magnet-pole main circuit metal motor needle negative north pole number of lines number of units ohms opposite direction pass placed plate platinum positive Power absorbed Practical Unit produced rent resistance revolved rise of temperature rotation secondary battery shown in Fig shunt Siemens soft iron south pole speed steel strength of current substance Suppose surface telegraphy tion tive transmitting tricity turns unit of electricity vibrations wire zinc
Popular passages
Page 52 - Ohm discovered the important law that " the strength of the current varies directly as the electro-motive force, and inversely as the resistance of the entire circuit.
Page 42 - The unit of force is that force which, acting for one second on a mass of one gramme, gives to it a velocity of one centimetre per second.
Page 15 - ... resumes its state of rest. The intensity of the magnetic force is determined from these oscillations in the same manner that the intensity of the gravitating and electrical forces are known from the vibrations of the pendulum and the balance of torsion, and in all these cases it is proportional to the square of the number of oscillations performed in a given time...
Page 97 - ... in the same direction as that in which the hands of a watch move, the line of sight being in both cases along the positive direction of the lines of force.
Page 54 - Unit of Resistance.— Solving the above equation with reference to R, So we see that a conductor has unit resistance when the current through it is equal numerically to the difference of electro-motive between its ends ; or when a difference of unit potential between its ends will produce a current of unit strength. Laws of Resistance. — 1. The resistance of a conductor is proportional to its length. A wire two miles long will have twice as much resistance as a similar wire one mile long. 2. The...
Page 136 - ... short mark upon the paper. In this way, then, the messages are recorded upon the paper strip in a sucFig. 96. cession of dots and dashes, which correspond to the dots and dashes signalled from the sending end, and which can be read off and translated into ordinary language. Multiplex Telegraphy. — By this term is meant the art of sending a number of messages over the same wire at the same time. To express the sending of two messages the term " duplex " is ordinarily employed, and to express...
Page 37 - This unit is, however, too large for measuring with convenience in many cases ; and for this reason a much smaller one has been invented, called the 'erg.
Page 73 - Nos. 337,298 and 337,299, are fundamental patents designed to cover the broad inventions of Mr. Brush. No. 260,654 is a division of Case J, and is distinguished by the inventor as "Case J, Division A." The invention "consists in the method of making the plates of a secondary battery consisting in forming receptacles for oxide of lead in its surface, then applying oxide of lead to the plates and within such receptacles and afterwards subjecting the oxide of lead to pressure.
Page 236 - The mechanical work given out by a motor is a maximum when the motor is geared to run at such a speed that the current is reduced to half the strength that it would have if the motor was stopped. This, of course, implies that the counter-electromotive force of the motor is equal to half the electromotive force furnished by the battery or generator.
Page 65 - The quantity of an ion liberated at an electrode in a given time, is proportional to the strength, of the current in amperes. III. The quantity of an ion liberated at an electrode in one second, is equal to the strength of the current multiplied by the "electro•chemical equivalent