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    المصطلحات الالكترونية

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    مُساهمة من طرف Admin في الثلاثاء فبراير 02, 2010 10:59 pm

    المصطلحات الالكترونية
    مرتبة أبجديا

    A
    Abbreviation for "ampere" a unit of electrical current

    absorption
    Loss or dissipation of energy as it travels through a medium, Example: radio waves lose some of their energy as they travel through the atmosphere.

    AC
    Abbreviation for "Alternating Current"

    acceptor atoms
    Trivalent atoms that accept free electrons from pentavalent atoms

    AC coupling
    Circuit that passes an AC signal while blocking a DC voltage.

    AC/DC
    Equipment that will operate on either an AC or DC power source.

    AC generator
    Device used to transform mechanical energy into AC electrical power.


    AC load line
    A graph representing all possible combinations of AC output voltage
    and current for an amplifier.

    AC power supply
    Power supply that delivers an AC voltage.

    active component
    A component that changes the amplitude of a signal between input and output.

    active filter
    A filter that uses an amplifier in addition to reactive components to pass or reject selected frequencies.

    active region
    The region of BJT operation between saturation and cutoff used for linear amplification.

    AC voltage
    A voltage in which the polarity alternates.

    ADC
    Abbreviation for "analog to digital converter"

    Admittance
    (symbol "Y") Measure of how easily AC will flow through a circuit. Admittance is the reciprocal of impedance and is measured in siemens.

    AF
    Abbreviation for "audio frequency".

    AFC
    Abbreviation for "automatic frequency control".

    AGC
    Abbreviation for "automatic gain control"


    alligator clip
    Spring clip on the end of a test lead used to make a temporary connection.

    alpha
    Ratio of collector current to emitter current in a bipolar junction transistor (BJT). Greek letter alpha "a" is the symbol used.


    alternator
    Name for an AC generator.

    AM
    Abbreviation for "amplitude modulation"

    ammeter
    A meter used to measure current.

    ampere
    Unit of electrical current.

    amplifier
    A circuit that increases the voltage, current, or power of a signal.

    amplitude:
    Magnitude or size of a signal voltage or current.

    analog
    Information represented as continously varying voltage or current rather than in discrete levels as opposed to digital data varying between two discrete levels.

    anode
    The positive electrode or terminal of a device. The "P" material of a diode.

    antenna, transmitting
    A device that converts an electrical wave into an electromagnetic wave that radiates away from the antenna.

    antenna, receiving
    A device that converts a radiated electromagnetic wave into an electrical wave.

    apparent power
    Power attained in an AC circuit as a product of effective voltage and current which reach their peak at different times.

    arc
    Discharge of electricity through a gas such as lightning discharging through the atmosphere.

    armature:
    The rotating or moving component of a magnetic circuit.


    astable multivibrator
    An oscillator that produces a square wave output from a DC voltage.

    atom
    The smallest particle that an element can be broken down into and still maintain its unique identity.

    atomic number
    The number of positive charges or protons in the nucleus of an atom.

    attenuate
    To reduce the amplitude of an action or signal. The opposite of amplification.

    autotransformer
    A single winding transformer where the output is taken from taps on the winding.

    average value
    A value of voltage or current where the area of the wave above the value equals the area of the wave below the value.

    AVC
    Abbreviation for "automatic volume control"

    avionics
    Aviation electronics.

    AWG
    Abbreviation for "american wire gauge". A gauge that assigns a number value to the diameter of a wire.
    =================================== =============== =======================
    B

    balanced bridge
    Condition that occurs when a bridge circuit is adjusted to produce a zero output.

    band-pass filter
    A tuned circuit designed to pass a band of frequencies between a lower cut-off frequency (f1) and a higher cut-off frequency (f2). Frequencies above and below the pass band are heavily attenuated.

    band-stop filter
    A tuned circuit designed to stop frequencies between a lower cut-off frequency (f1) and a higher cut-off frequency (f2) of the amplifier while passing all other frequencies.

    bandwidth
    Width of the band of frequencies between the half power points.

    barrier potential
    The natural difference of potential that exists across a forward biased pn junction.

    base
    The region that lies betwen the emitter and collector of a bipolar junction transistor (BJT).

    base biasing
    A method of biasing a BJT in which the bias voltage is supplied to the base by means of a resistor.

    battery
    A DC voltage source containing two or more cells that convert chemical energy to electrical energy.

    baud
    A unit of signaling speed equal to the number of signal events per second. Not necessarily the same as bits per second.

    beta
    (b) The ratio of collector current to base current in a bipolar junction transistor (BJT).

    bias
    A DC voltage applied to a device to control its operation.

    binary
    A number system having only two symbols, 0 and 1. A base 2 number system.

    bipolar junction transistor
    (BJT), A three terminal device in which emitter to collector current is controlled by base current.

    bistable multivibrator
    A multivibrator with two stable states. An external signal is required to change the output from one state to the other. Also called a latch.

    bleeder current
    A current drawn continously from a souce. Bleeder current is used to stabilize the output voltage of a source.

    bode plot
    A graph of gain versus frequency.

    branch current
    The portion of total current flowing in one path of a parallel circuit.

    breakdown voltage
    Voltage at which the breakdown of a dialectric or insulator occurs.

    breakover voltage
    Minimum voltage required to cause a diac to break down and conduct.

    bridge rectifier
    A circuit using four diodes to provide full wave rectification. Converts an AC voltage to a pulsating DC voltage.


    buffer
    An amplifier used to isolate a load from a source.

    bulk resistance
    The natural resistance of a "P" type or "N" type semiconductor material.

    butterworth filter
    A type of active filter characterized by a constant gain (flat response) across the midband of the circuit and a 20 dB per decade roll-off rate for each pole contained in the circuit.

    BW
    Abbreviation for bandwidth.

    bypass capacitor
    A capacitor used to provide an AC ground at some point in a circuit.

    byte
    Group of eight binary digits or bits.
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    مُساهمة من طرف Admin في الثلاثاء فبراير 02, 2010 11:02 pm

    size=16]cable
    [/size]
    Group of two or more insulated wires.

    CAD
    Abbreviation for "computer aided design"

    calibration
    To adjust the correct value of a reading by comparison to a standard.

    capacitance
    The ability of a capacitor to store an electrical charge. The basic unit of capacitance is the Farad.

    capacitive reactance
    The opposition to current flow provided by a capacitor. Capacitive reactance is measured in ohms and varies inversly with frequency.

    capacitor
    An electronic component having capacitive reactance.

    capacitor microphone
    Microphone whose operation depends on variations in capacitance caused by varying air pressure on the movable plate of a capacitor.

    carbon-film resistor
    Device made by depositing a thin carbon film on a ceramic form.

    carbon microphone
    Microphone whose operation depends on pressure variation in carbon granules causing a change in resistance.

    carbon resistor
    Resistor of fixed value made by mixing carbon granules with a binder which is moulded and then baked.

    cascaded amplifier
    An amplifier with two or more stages arranged in a series configuration.

    cascode amplifier
    A high frequency amplifier made up of a common-source amplifier with a common-gate amplifier in its drain network.

    cathode
    The negative terminal electrode of a device. The "N" material in a junction diode.

    cathode ray tube
    (CRT) Vacuum tube used to display data in a visual form. Picture tube of a television or computer terminal.

    cell
    Single unit used to convert chemical energy into a DC electrical voltage.

    center frequency
    Frequency to which an amplifier is tuned. The frequency half way between the cut-off frequencies of a tuned circuit.

    center tap
    Midway connection between the two ends of a winding.

    center tapped rectifier
    Circuit that make use of a center tapped transformer and two diodes to provide full wave rectification.

    center tapped transformer
    A transformer with a connection at the electrical center of a winding.

    ceramic capacitor
    Capacitor in which the dialectric is ceramic.

    charge
    Quantity of electrical energy.

    charge current
    Current that flows to charge a capacitor or battery when voltage is applied.

    chassis
    ****l box or frame into which components are mounted.

    chassis ground
    Connection to a chassis.

    chebyshev filter
    A type of active filter characterized by high roll-off rates (40 dB per decade per pole) and midband gain that is not constant.

    choke
    Inductor used to oppose the flow of alternating current.

    circuit
    Interconnection of components to provide an electrical path between two or more components.

    circuit breaker
    A protective device used to open a circuit when current exceeds a maximum value. In effect a reusable fuse.

    clamper
    A diode circuit used to change the DC level of a waveform without distorting the waveform.

    clapp oscillator
    A variation of the Colpitts oscillator. An added capacitor is used to eliminate the effects of stray capacitance on the operation of the basic Colpitts oscillator.

    class A amplifier
    A linear amplifier biased so the active device conducts through 360 degrees of the input waveform.

    class B amplifier
    An amplifier with two active devices. The active components are biased so that each conducts for approximately 180 degrees of the input waveform cycle.

    class C amplifier
    An amplifier in which the active device conducts for less than 180 degrees of the input waveform cycle.

    clipper
    A diode circuit used to eliminate part of a waveform

    clipping
    Distortion caused by overdriving an amplifier.

    clock
    A square waveform used for synchronizing and timing of several circuits.

    closed circuit
    Circuit having a complete path for current flow.


    coaxial cable
    Transmission line in which the signal carrying conductor is covered by a dialectric and another conductor.

    coefficient of coupling
    The degree of coupling between two circuits.

    ]coercive force
    (H) Magnetizing force needed to reduce residual magnetism in a material to zero.

    [collector
    The semiconductor region in a bipolar junction transistor through which a flow of charge carriers leaves the base region.

    collector characteristic curve
    A graph of collector voltage over collector current for a given base current.

    color code
    Set of colors used to indicate value of a component.


    common-anode display
    A multisegment light emitting diode (LED) with a single positive voltage input connection. Separate cathode connections are provided for each individual segment.

    common cathode display
    A multisegment light emitting diode (LED) with a single negative voltage input connection. Separate anode connections are provided for each individual segment.

    common base amplifier

    A BJT circuit in which the base connection is common to both input and output.

    common collector amplifier
    A BJT circuit in which the collector connection is common to both input and output.

    common drain amplifier
    A FET circuit in which the drain connection is common to both input and output.

    common emitter amplifier
    A BJT circuit in which the emitter connection is common to both input and output.

    common gate amplifier
    A FET circuit in which the gate connection is common to both input and output.

    common source amplifier
    A FET circuit in which the source connection is common to both input and output.

    common-mode rejection ratio

    (CMRR) The ratio of op-amp differential gain to common-mode gain. A measure of an op-amp's ability to reject common-mode signals such as noise.

    common-mode signals
    Signals that appear simultaneously at two inputs of an operational amplifier (op-amp). Common mode signals are always equal in amplitude and phase.

    comparitor
    An op-amp circuit that compares two inputs and provides a DC output indicating the polarity relationship between the inputs.

    complementary symmetry amplifier

    A class B amplifier using matched complementry transistors. Does not require a phase inverter for push-pull output.

    complementry transistors
    Two transistors, one NPN and one PNP having near identical charastics. N-channel and P-channel FETs can also be complementry.

    complex numbers
    Numbers composed of a real number part and an imaginary number part.

    compliance
    The maximum possible peak-to-peak output of an amplifier.

    constant current circuit

    Circuit used to maintain constant current to a load having resistance that changes.

    contact
    Current carrying part of a switch, relay or connector.

    continuity
    Occurs when a complete path for current exists.

    conventional current flow

    Concept of current produced by the movement of positive charges towards the negative terminal of a source.

    copper loss
    Power lost in transformers, generators, connecting wires and other parts of a circuit due to current flow through the resistance of copper conductors.

    core
    Magnetic material within a coil used to concentrate the magnetic field.

    coulomb
    Unit of electric charge. A negative coulomb charge consists of 6.24 × 1018 electrons.

    counter electromotive force
    (counter emf) Voltage induced into an inductor due to an alternating or pulsating current. Counter emf is always in polarity opposite to that of the applied voltage. Opposing a change of current.

    coupling
    To electronically connect two circuits so that signal will pass from one to the other.

    Feed configuration where a portion of the output current is fed to the amplifier input

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