SWITCH(1) A device used to connect, disconnect, or change the connections in an electrical circuit .
(2) A device used to open or close a circuit .
SYMMETRICAL MULTIVIBRATORA circuit that generates square waves .
SYMPTOM ELABORATIONUsing built-in indicating instruments or other aids to define equipment
SYMPTOM RECOGNITIONRecognition of a situation in equipment operation that is not normal .
SYNCHROA small motorlike analog device that operates like a variable transformer and is used
primarily for the rapid and accurate transmission of data among equipments and stations .
SYNCHRO CAPACITORA unit containing three delta-connected capacitors. The synchro capacitor is
used in synchro systems to increase the system's accuracy by cancelling or reducing the phase shift
introduced by synchro inductance .
SYNCHRONIZERA circuit that supplies timing signals to other radar components .
SYNCHRONIZING NETWORKA circuit, also called a crossover or switching network, used in
servosystems to sense how far the load is from the point of correspondence; it then functions to switch
the appropriate signal into control .
SYNCHRONOUSA type of teletypewriter operation where both transmitter and receiver operate
SYNCHRONOUS MOTORAn ac motor whose rotor is activated by dc. It is characterized by constant
speed and requires squirrel-cage windings or some other method to be self-starting .
SYNCHRONOUS ORBITAn orbit in which the satellite moves or rotates at the same speed as the earth
SYNCHRONOUS SPEEDThe speed at which the rotating field in an ac motor revolves. This speed is a
function of the number of poles in the field and the frequency of the applied voltage .
SYNCHRONOUS TUNINGIn a klystron amplifier, a method of tuning that tunes all the resonant
cavities to the same frequency. High gain is achieved, but the bandwidth is narrow .
SYNCHRO SYSTEMTwo or more synchros interconnected electrically. The system is used to transmit
data among equipments and stations .
SYNCHRO TESTERA synchro receiver with a calibrated dial. This receiver is used primarily for
locating defective synchros. It can also be used for zeroing synchros .
SYSTEMA combination of sets, units, assemblies, subassemblies, and parts joined together to form a
specific operational function or several functions .
TACHOMETER(1) A small ac or dc generator, sometimes referred to as a rate generator, that converts
its shaft speed into an electrical output. The tachometer is frequently used in servosystems to sense the
velocity of a load . (2) An instrument that measures the rate at which a shaft is turning .
TANK CIRCUITA tuned circuit used to temporarily store energy. Also referred to as a parallel-resonant