audio-frequency electromagnetic method
51telephone — telephoner, n. /tel euh fohn /, n., v., telephoned, telephoning. n. 1. an apparatus, system, or process for transmission of sound or speech to a distant point, esp. by an electric device. v.t. 2. to speak to or summon (a person) by telephone. 3.… …
52Burglar alarm — Silent alarm redirects here. For the album, see Silent Alarm (album). Burglar (or intrusion), fire and safety alarms are all electronic today. Sensors are connected to a control unit via a low voltage hardwire or narrowband RF signal which is… …
53Radio communication system — A radio communication system send signals by radio. [cite book | title = Wireless Network Performance Handbook | author = Clint Smith, Curt Gervelis | year = 2003 | publisher = McGraw Hill Professional | isbn = 0071406557 | url =… …
54electricity — /i lek tris i tee, ee lek /, n. 1. See electric charge. 2. See electric current. 3. the science dealing with electric charges and currents. 4. a state or feeling of excitement, anticipation, tension, etc. [1640 50; ELECTRIC + ITY] * * *… …
55Nobel Prizes — ▪ 2009 Introduction Prize for Peace The 2008 Nobel Prize for Peace was awarded to Martti Ahtisaari, former president (1994–2000) of Finland, for his work over more than 30 years in settling international disputes, many involving ethnic,… …
56Computer security compromised by hardware failure — is a branch of computer security applied to hardware. The objective of computer security includes protection of information and property from theft, corruption, or natural disaster, while allowing the information and property to remain accessible …
57Signals intelligence — SIGINT redirects here. For the UNIX signal, see SIGINT (POSIX). RAF Menwith Hill, a large site in the United Kingdom, part of ECHELON and the UK USA Security Agreement. Signals intelligence (often contracted to SIGINT) is intelligence gathering… …
58Capacitor — This article is about the electronic component. For the physical phenomenon, see capacitance. For an overview of various kinds of capacitors, see types of capacitor. Capacitor Modern capacitors, by a cm ruler Type Passive …
59telecommunication — [tel΄ə kə myo͞o΄ni kā′shən] n. [also pl., with sing. or pl. v.] communication by electronic or electric means, as through radio, telephone, telegraph, television, or computers * * * tel·e·com·mu·ni·ca·tion (tĕlʹĭ kə myo͞o nĭ kāʹshən) n. 1. The… …
60Alternating current — (green curve). The horizontal axis measures time; the vertical, current or voltage. In alternating current (AC, also ac) the movement of electric charge periodically reverses direction. In direct current (DC, also dc), the flow of electric charge …
