Electronics (Mike Jaroch)
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PACKAGING LEVELSA system developed to assist maintenance personnel in determining the repairability of components, printed circuit boards, modules, and so forth [14]. | ||
PAGE PRINTERA high-speed printer that prints teletypewriter characters one at a time in a full-page format [17]. | ||
PARABOLIC REFLECTORAn antenna reflector in the shape of a parabola. It converts spherical wavefronts from the radiating element into plane wavefronts [18]. | ||
PARALLEL CIRCUITTwo or more electrical devices connected to the same pair of terminals so separate currents flow through each; electrons have more than one path to travel from the negative to the positive terminal [1]. | ||
PARALLEL LIMITERA resistor and diode, connected in series with the input signal, in which the output is taken across (parallel to) the diode [9]. | ||
PARALLEL-CONNECTED DUPLEXERConfiguration in which the tr spark gap is connected across the two legs of the transmission line one-quarter wavelength from the T-junction [18]. | ||
PARALLEL-NEGATIVE LIMITERA resistor and diode, connected in series with the input signal, in which the output is taken across the diode and the negative alternation is eliminated [9] | ||
PARALLEL-POSITIVE LIMITERA resistor and diode connected in series with the input signal, in which the output is taken across the diode and the positive alternation is eliminated [9]. | ||
PARALLEL-RESONANT CIRCUITA resonant circuit in which the source voltage is connected across a parallel circuit (formed by a capacitor and an inductor) to furnish a high impedance to the frequency at which the circuit is resonant. Often referred to as a tank circuit [9] [10]. | ||
PARALLEL-WIREA type of transmission line consisting of two parallel wires [10]. | ||
PARASITIC ARRAYAn antenna array containing one or more elements not connected to the transmission line [10] [18]. | ||
PARASITIC ELEMENTThe passive element of an antenna array that is connected to neither the transmission line nor the driven element [10]. | ||
PARTA part is one component or two or more components joined together. It is not normally subject to disassembly without destruction [17]. | ||
PASSIVE SATELLITEA satellite that reflects radio signals back to earth [17]. | ||
PATCH PANELA panel used to tie a receiver or transmitter to its associated equipment [17]. | ||
PEAK AMPLITUDEThe maximum value above or below the reference line [12]. | ||
PEAK CURRENTThe maximum current that flows during a complete cycle [6]. | ||
PEAK DETECTIONDetection that uses the amplitude of pam or the duration of pdm to charge a holding capacitor and restore the original waveform [12] | ||
PEAK POWERThe maximum value of the transmitted pulse [12]. | ||
PEAK VALUEThe maximum instantaneous value of a varying current, voltage, or power. It is equal to 1.414 times the effective value of a sine wave [2]. | ||
PEAK VOLTAGEThe maximum value present in a varying or alternating voltage. This value may be positive or negative [6]. | ||
PEAK-REVERSE VOLTAGEThe peak ac voltage that a rectifier tube will withstand in the reverse direction [6]. | ||
PEAK-TO-PEAKThe measure of absolute magnitude of an ac waveform, measured from the greatest positive alternation to the greatest negative alternation [2]. | ||
PEAKING COILAn inductor used in an amplifier to provide high-frequency compensation, which extends the high-frequency response of the amplifier [8]. | ||
PENTAVALENT IMPURITYA type of impurity that contains five valence electrons and donates one electron to the doped material. Also called DONOR IMPURITY [7]. | ||
PENTODE TUBEA five-electrode electron tube containing a plate, a cathode, a control grid, and two grids [6]. | ||
PERCENT OF MODULATIONThe degree of modulation defined in terms of the maximum permissible amount of modulation [12]. | ||
PERFORATORA device that stores a teletypewriter message on a paper tape [17]. | ||
PERIGEEThe point in the orbit of a satellite closest to the earth [17]. | ||
PERIOD TIMEThe time required to complete one cycle of a waveform [2] [10] [12]. | ||
PERIODIC WAVEA waveform that undergoes a pattern of changes, returns to its original pattern, and then repeats the same pattern of changes. Examples are square waves, rectangular waves, and sawtooth waves [9]. | ||
PERMANENT MAGNET SPEAKERA speaker with a permanent magnet mounted on soft iron pole pieces [17]. | ||
PERMEABILITYThe measure of the ability of a material to act as a path for magnetic lines of force [1] [8]. | ||
PERSISTENCEThe length of time a phosphor dot glows on a CRT before disappearing [6] [18]. | ||
PHANTASTRONA variable-length sawtooth generator often used to produce a sweep on an A-scope [18]. | ||
PHASEThe angular relationship between two alternating currents or voltages when the voltage or current is plotted as a function of time. When the two are in phase, the angle is zero; both reach their peak simultaneously. When out of phase, one will lead or lag the other; that is, at the instant when one is at its peak, the other will not be at peak value and (depending on the phase angle) may differ in polarity as well as magnitude [2]. | ||
PHASE ANGLEThe number of electrical degrees of lead or lag between the voltage and current waveforms in an ac circuit [2] [12]. | ||
PHASE MODULATION(pm)—Angle modulation in which the phase of the carrier is controlled by the modulating waveform. The amplitude of the modulating wave determines the amount of phase shift, and the frequency of the modulation determines how often the phase shifts [12]. | ||
PHASE SHIFTERA device used to change the phase relationship between two ac signals [11]. | ||
PHASE SPLITTERA device that provides two output signals from a single input signal. The two output signals differ from each other in phase (usually by 180 degrees) [8]. | ||
PHASE-SHIFT DISCRIMINATORSee FOSTER-SEELEY DISCRIMINATOR [12]. | ||
PHASE-SHIFT KEYINGSimilar to ON-OFF cw keying in AM systems and frequency-shift keying in FM systems. Each time a mark is received, the phase is reversed. No phase reversal takes place when a space is received [12]. | ||
PHOSPHORThe material used to convert the energy of electrons into visible light [6]. | ||
PHOTOCELLA light-controlled variable resistor which has a light-to-dark resistance ratio of 1:1000. Used in various types of control and timing circuits [7]. | ||
PHOTODIODEA light-controlled PN junction. Current flow increases when the PN junction is exposed to an external light source [7]. | ||
PHOTOELECTRIC VOLTAGEA voltage produced by light [1]. | ||
PHOTOETCHINGChemical process of removing unwanted material in producing printed circuit boards [14]. | ||
PHOTOTRANSISTORAn optoelectronic device that conducts current when exposed to light. Produces more current and is much more sensitive to light than the photodiode [7]. | ||
PHOTOVOLTAIC CELL(SOLAR CELL)—A device that acts much like a battery when exposed to light and converts light energy into electrical energy [7]. | ||
PICOA prefix adopted by the National Bureau of Standards meaning 10 -12 [1]. | ||
PICTORIAL DIAGRAMA diagram showing actual pictorial sketches of the various parts of an equipment and the electrical connections between the parts [4]. | ||
PIEZOELECTRIC EFFECTThe effect of producing a voltage by placing a stress, either by compression, expansion, or twisting, on a crystal and, conversely, producing a stress in a crystal by applying a voltage to it [1]. | ||
PIP PIP (BLIP)—On a CRT display, a spot of light or a baseline irregularity representing the radar echo [18]. | ||
PITCHA term used to describe the frequency of a sound heard by the human ear [10]. | ||
PLANAR TUBEAn electron tube, constructed with parallel electrodes and a ceramic envelope, that is used at uhf frequencies. It is commonly referred to as a lighthouse tube [6]. | ||
PLANE OF POLARIZATIONThe plane (vertical or horizontal), with respect to the earth, in which the E field propagates [10]. | ||
PLANE WAVEFRONTSWaves of energy that are flat, parallel planes and are perpendicular to the direction of propagation [18]. | ||
PLANNED-POSITION INDICATORA radar display in which range is indicated by the distance of a bright spot or pip from the center of the screen and the bearing is indicated by the radial angle of the spot [18]. | ||
PLATE(1) One of the electrodes in a storage battery [1]. (2) One of the electrodes in a capacitor [2]. (3) The principal electrode to which the electron stream is attracted in an electron tube [6]. | ||
PLATE DISSIPATIONThe amount of power lost as heat in the plate of a vacuum tube [6]. | ||
PLATE KEYINGA keying system in which the plate supply is interrupted [12]. | ||
PLATE MODULATORAn electron-tube modulator in which the modulating voltage is applied to the plate circuit of the tube [12]. | ||
PLATE RESISTANCEThe plate voltage change divided by the resultant plate current change in a vacuum tube, all other conditions being fixed [6]. | ||
POINT BENDERA tool used to adjust the contact spacing on a relay [3]. | ||
POINT OF ZERO DISPLACEMENTSee REFERENCE LINE [10]. | ||
POINT-CONTACT DIODEA diode in which the end of a fine wire is pressed against a semiconductor. Used as a detector or mixer over the microwave region [7]. | ||
POINT-TO-POINT WIRINGIndividual wires run from terminal to terminal to complete a circuit [14]. | ||
POLARThe teletypewriter operation in which current flow of one polarity represents a mark, and current of the opposite polarity represents a space [17]. | ||
POLAR ORBITAn orbit that has an angle of inclination of or near 90 degrees [17]. | ||
POLAR-COORDINATE GRAPHA graph with a pair of axes. One consists of a series of circles with a common center, and the other consists of a rotating radius extending from the center of the concentric circles [10]. | ||
POLARITY(1) The condition in an electrical circuit by which the direction of the flow of current can be determined. Usually applied to batteries and other direct voltage sources. (2) Two opposite charges, one positive and one negative. (3) A quality of having two opposite magnetic poles, one north and the other south [1] [13]. | ||
POLARIZATION(1) The effect of hydrogen surrounding the anode of a cell, which increases the internal resistance of the cell [1]. (2) The magnetic orientation of molecules in a magnetizable material in a magnetic field, whereby tiny internal magnets tend to line up in the field [2]. | ||
POLE(1) The number of points at which current can enter a switch; for example, single pole, double pole, and three pole [3]. (2) The sections of a field magnet where the flux lines are concentrated; also where they enter and leave the magnet [5]. | ||
POLE PIECE(1) A piece of ferromagnetic material used to control the distribution of magnetic lines of force; that is, it concentrates the lines of force in a particular place or evenly distributes the lines of force over a wide area [3]. (2) The shaped magnetic material upon which the stator windings of motors and generators are mounted or wound [5]. | ||
POLYMER FUME FEVERA flu-like condition caused by a person breathing the vapors of fluorocarbons when they are heated. Sometimes called FOUNDRYMAN'S FEVER [4]. | ||
POLYPHASEA term that describes systems or units of a system that are activated by or which generate separate out-of-phase voltages. Typical polyphase systems are 2-phase and 3-phase; their voltages are 90- and 120-degrees out of phase, respectively. This term means the same as MULTIPHASE [5]. | ||
POSITION SENSORA component in a servosystem that measures position and converts the measurement into a form convenient for transmission as a feedback signal [15]. | ||
POSITION SERVOSYSTEMA servosystem whose end function is to control the position of the load it is driving [15]. | ||
POSITIONAL NOTATIONA numbering system in which a number is represented by means of a stated set of symbols or digits, such that the value contributed by each symbol or digit depends upon its position as well as upon its value [13]. | ||
POSITIONAL WEIGHTINGThe value given a digit based on the digit's position within a given number [13]. | ||
POSITIVE ALTERNATIONThe part of a sine wave that is above the reference line [2] [10] [12]. | ||
POSITIVE CLAMPERA circuit that clamps the lower extremity of the output waveshape to a dc potential of 0 volts [9]. | ||
POSITIVE FEEDBACKFeedback in which the feedback signal is in phase with the input signal. Also called REGENERATIVE FEEDBACK [8]. | ||
POSITIVE LOGICThe form of logic in which the more positive logic level represents 1 and the more negative level represents 0 [13]. | ||
POSITIVE TEMPERATURE COEFFICIENTThe characteristic of a conductor in which the resistance increases as temperature increases [7]. | ||
POTENTIAL ENERGYEnergy caused by the position of one body with respect to another body or to the relative parts of the same body [1]. | ||
POTENTIOMETERA variable resistor, used as a position sensor in servosystems, having a terminal connected to each end of a resistive element and a third terminal connected to a wiper contact. The output is a voltage that is variable depending upon the position of the wiper contact. The potentiometer is commonly referred to as a variable voltage divider. It, in effect, converts mechanical information into an electrical signal [1] [15]. | ||
POWERThe rate of doing work or the rate of expending energy. The unit of electrical power is the watt [1]. | ||
POWER AMPLIFIERAn amplifier in which the output-signal power is greater than the input-signal power [8]. | ||
POWER FACTORThe ratio of the actual power of an alternating or pulsating current, as measured by a wattmeter, to the apparent power, as indicated by ammeter and voltmeter readings. The power factor of an inductor, capacitor, or insulator is an expression of their losses [2] [16]. | ||
POWER GAINIn an antenna, the ratio of its radiated power to that of a reference [11] [18]. | ||
POWER LOSS(1) The electrical power, supplied to a circuit, that does no work and is usually dissipated as heat [2] [4]. (2) The heat loss in a conductor as current flows through it [10]. | ||
POWER PENTODEA special purpose tube used to provide high-current gain or power mplification. Each grid wire is directly in line with the one before and after it, a fact which allows more electrons to reach the plate [6]. | ||
POWER RATIOSee POWER GAIN [11]. | ||
POWER STANDING-WAVE RATIOThe ratio of the square of the maximum and minimum voltages of a transmission line [10]. | ||
POWER SUPPLYA unit that supplies electrical power to another unit. It changes ac to dc and maintains a constant voltage output within limits [6] [7]. | ||
POWER-AMPLIFIER TRANSMITTERTransmitter that uses a series of power amplifiers to create a high level of power [18]. | ||
PREAMPLIFIERAn amplifier that raises the output of a low-level source for further processing without appreciable degradation of the signal-to-noise ratio [18]. | ||
PRECESSIONThe rotation of the spin axis of a gyro in response to an applied force. The direction of precession is always perpendicular to the direction of applied force [15]. | ||
PRECESSION VECTORIn a gyro, a vector representing the angular change of the spin axis when torque is applied. The precession vector represents the axis about which precession occurs [15]. | ||
PRESTANDARD NAVY SYNCHROSSynchros that are designed to meet Navy, rather than servicewide, specifications [15]. | ||
PREVENTIVE MAINTENANCEVisual, mechanical, electrical, and electronic checks that are made to determine whether or not equipment is functioning properly [16]. | ||
PRIMARIESPRIMARIES (OF LIGHT)—The three primary colors of light from which all other colors can be derived. The colors are red, green, and blue [10]. | ||
PRIMARY CELLAn electrochemical cell in which the chemical action eats away one of the electrodes, usually the negative electrode [1]. | ||
PRIMARY LOOPIn a cooling system, the primary source of cooling for the distilled water [18]. | ||
PRIMARY WINDINGThe winding of a transformer connected to the electrical source [2]. | ||
PRIME MOVERThe source of the turning force applied to the rotor of a generator. This may be an electric motor, a gasoline engine, a steam turbine, and so forth [5]. | ||
PRINTED CIRCUIT BOARDA flat, insulating surface upon which printed wiring and miniaturized components are connected in a predetermined design and attached to a common base [7] [14]. | ||
PRISMA triangular-shaped glass that refracts and disperses light waves into component wavelengths [10]. | ||
PROBE COUPLERA resonant conductor placed in a waveguide or cavity to insert or extract energy [18]. | ||
PROGRAMMED TRACKINGThe method that uses known satellite orbital parameters to generate antenna pointing angles [17]. | ||
PROPAGATIONWaves traveling through a medium [10]. | ||
PULSESignal characterized by a steep rise from and decay toward an initial level [9] [12]. | ||
PULSE DURATIONPULSE DURATION (PD)—The period of time during which a pulse is present [12]. | ||
PULSE MODULATIONA form of modulation in which one of the characteristics of a pulse train is varied [12]. | ||
PULSE OSCILLATORA sine-wave oscillator that is turned on and off at specific times. Also known as a ringing oscillator [9]. | ||
PULSE WIDTHDuration of time between the leading and trailing edges of a pulse [12] [18]. | ||
PULSE-AMPLITUDE MODULATIONPULSE-AMPLITUDE MODULATION (PAM)—Pulse modulation in which the amplitude of the pulses is varied by the modulating signal [12]. | ||
PULSE-CODE MODULATIONPULSE-CODE MODULATION (PCM)—A modulation system in which the standard values of a quantized wave are indicated by a series of coded pulses [12]. | ||
PULSE-DURATION MODULATIONPULSE-DURATION MODULATION (PDM)—Pulse modulation in which the time duration of the pulses is changed by the modulating signal [12]. | ||
PULSE-FORMING NETWORKPULSE-FORMING NETWORK (PFN)—An lc network that alternately stores and releases energy in an approximately rectangular wave [12] [18]. | ||
PULSE-FREQUENCY MODULATIONPULSE-FREQUENCY MODULATION (PFM)—Pulse modulation in which the modulating voltage varies the repetition rate of a pulse train [12]. | ||
PULSE-POSITION MODULATIONPULSE-POSITION MODULATION (PPM)—Pulse modulation in which the position of the pulses is varied by the modulating voltage [12]. | ||
PULSE-REPETITION FREQUENCYPULSE-REPETITION FREQUENCY (PRF)—The rate, in pulses per second, at which the pulses occur [9] [12] [18]. | ||
PULSE-REPETITION RATEPULSE-REPETITION RATE (PRR)—Same as PULSE-REPETITION FREQUENCY (PRF) [9] [12] [18]. | ||
PULSE-REPETITION TIMEPULSE-REPETITION TIME (PRT)—Interval between the start of one pulse and the start of the next pulse; reciprocal of pulse-repetition frequency [18]. | ||
PULSE-TIME MODULATIONPULSE-TIME MODULATION (PTM)—Pulse modulation that varies one of the time characteristics of a pulse train (pwm, pdm, ppm, or pfm) [12]. | ||
PULSE-WIDTH MODULATIONPULSE-WIDTH MODULATION (PWM)—Pulse modulation in which the duration of the pulses is varied by the modulating voltage [12]. | ||
PULSINGAllowing oscillations to occur for a specific period of time only during selected intervals [12]. | ||
PUMPElectrical source of the energy required to vary the capacitance of a parametric amplifier [11]. | ||
PUSH-PULL AMPLIFIERAn amplifier that uses two transistors (or electron tubes) whose output signals are in phase opposition [8]. | ||