rotary switching system
21Uninterruptible power supply — A small free standing UPS …
22Electric motor — For other kinds of motors, see motor (disambiguation). For a railroad electric engine, see electric locomotive. Various electric motors. A 9 volt PP3 transistor battery is in the center foreground for size comparison. An electric motor converts… …
23Telephone exchange — A telephone operator manually connecting calls with cord pairs at a telephone switchboard. In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls. A central… …
24gasoline engine — Most widely used form of internal combustion engine, found in most automobiles and many other vehicles. Gasoline engines vary significantly in size, weight per unit of power generated, and arrangement of components. The principal type is the… …
25Orbital replacement unit — Orbital Replacement Units (ORUs) are key elements of the International Space Station that can be readily replaced when the unit either passes its design life or fails. Examples of ORUs are: pumps, storage tanks, controller boxes, antennas, and… …
26Dual-tone multi-frequency signaling — One of the few production telephone DTMF keypads with all 16 keys, from an Autovon Telephone. The column of red keys produces the A, B, C, and D DTMF events. Dual tone multi frequency signaling (DTMF) is used for telecommunication signaling over… …
279-1-1 — This article is about the emergency telephone number. For other uses, see 911 (disambiguation). See also: Emergency telephone number Emergency 911 displayed on the side of an emergency vehicle, indicating that 9 1 1 is the number to dial in the… …
28Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity. Computer scientist Manindra Agrawal of the… …
29Personal rapid transit — ation concept that offers on demand, non stop transportation, using small, independent vehicles on a network of specially built guideways. Several different designs have been proposed, and as of 2008, at least one is under… …
30George Westinghouse — Infobox Scientist name = George Westinghouse caption = birth date = birth date|1846|10|6 birth place = Central Bridge, New York death date = death date and age|1914|03|12|1846|10|06 death place = New York, New York residence = citizenship =… …
