Search results
Results from the WOW.Com Content Network
Streetcars created enormous demand for early electricity. This Siemens Tram from 1884 required 500 V direct current, which was typical. Much of early electricity was direct current, which could not easily be increased or decreased in voltage either for long-distance transmission or for sharing a common line to be used with multiple types of electric devices.
Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Electric power, like mechanical power, is the rate of doing work, measured in watts, and represented by the letter P. The term wattage is used colloquially
History of electricity can refer to: See Electricity § History for an overview; History of electromagnetic theory; History of electrical engineering;
The transmitter Witzleben uses the new standard with 441 lines and 25 image changes, i.e. 50 fields of 220 half-lines. Until the HDTV era the interlace method remains in use. First movie encoder make it possible not to send the TV live, but to rely on recordings. 1938 The improved AEG tape-recorder "Magnetophon K4" is first used in radio studios.
A simple electromagnet, consisting of an insulated wire wound around an iron core. An electric current passing through the wire creates a Magnetic field, with a north pole at one end and a south pole at the other. The first application of electricity that was put to practical use was electromagnetism. [18]
The first half of the 700-page book is a history of the study of electricity. It is parted into ten periods, starting with early experiments "prior to those of Mr. Hawkesbee", finishing with variable experiments and discoveries made after Franklin's own experiments.
In the early 1930s, a gel electrolyte (instead of a liquid) produced by adding silica to a charged cell was used in the LT battery of portable vacuum-tube radios. In the 1970s, "sealed" versions became common (commonly known as a "gel cell" or "SLA"), allowing the battery to be used in different positions without failure or leakage.
The Electric Lighting (Clauses) Act 1899 (repealed 1989) introduced common principles for provisional orders; prohibited the amalgamation of undertakings and the supply of electricity outside a prescribed area.