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94 Cards in this Set
- Front
- Back
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What consists of a coil and a capacitor connected in series or parallel?
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Tuned circuit
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What phenomenon takes place whenever the characteristics of inductance and capacitance are found in a tuned circuit?
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Resonance
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In an AC circuit, an inductor produces inductive reactance which causes the current to lag the voltage by how many degrees?
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90
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What is the opposition a capacitor presents to AC called?
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Capacitive reactance |
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What is the difference called between the individual reactances in a seriescircuit?
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Resultant reactance |
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Resonant circuits may be designed as series resonant or what else? |
Parallel resonant |
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What is the ability to discriminate between frequencies known as? |
Selectivity |
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What is a parallel-LC circuit often called because it can store energy much as a tank stores liquid? |
Tank circuit |
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What must a circuit have that is completed and has a voltage applied, buthas zero current?
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Infinite impedance |
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What is a direct and accurate measure of the quality of an LC circuit?
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Q |
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What governs reactance at a given frequency?
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Inductance |
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What refers to the fact that at resonance, the voltage drop across the reactances are greater than the applied voltage?
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Gain |
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The range of frequencies included between the two frequencies at which the current drops to what percent of its maximumvalue at resonance is called the bandwidth of the circuit?
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70 |
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How many general types can filter circuits be divided into?
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Four |
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What is the electronic filter known as that can pass on the higher-frequency components to a load or to the next circuit?
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High-pass filter |
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What passes on a majority of the low frequencies to the next circuit and rejects or attenuates the higher frequencies?
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Low-pass filter |
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What is the ability of the filter circuit to distinguish between high and low frequencies and to eliminate or reject the unwantedfrequencies known as?
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Discrimination |
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What is the ability of the filter circuit to reduce the amplitude of the unwanted frequencies below the level of the desiredoutput frequency known as? |
Attenuation |
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What is the frequency at which the filter circuit changes from the point of rejecting the unwanted frequencies to thepoint of passing the desired frequency?
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Frequency cutoff |
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The bandpass filter and the band-reject filter are two common types of filters that use which type of circuits?
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Resonant |
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Which type of circuit is used to block the passage of current for a narrow band of frequencies, while allowing current to flowat all frequencies above or below this band?
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Band-reject filter |
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What property of a circuit is the range of frequencies between the half-powerpoints?
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Bandwidth |
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What consists of a combination of capacitors, inductors, and resistors connected so that the filter will either permit orprevent passage of a certain band of frequencies?
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Filter circuit |
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What can be regarded as an amplifier which provides its own input signal?
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Oscillator |
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Which two broad categories according to their output waveshapes can wave generators be classified into?
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Sinusoidal and Nonsinusoidal |
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Which type of oscillator produces a sine-wave output signal?
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Sinusoidal |
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Many low-frequency generators use resistors and capacitors to form their frequency- determining networks and arereferred to as what?
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RC Oscillators |
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Which type of sine-wave generator uses inductors and capacitors for its frequency- determining network?
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LC Oscillator |
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Which type of oscillator provides excellent frequency stability and is used from the middle of the audio range through theradio frequency range?
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Crystal controlled |
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Which type of oscillators generate complex waveforms, such as square, rectangular, trigger, sawtooth, or trapezoidal?
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Nonsinusoidal |
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Which device acts as a filter, allowing only the desired frequency to pass?
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Frequency-determining |
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Which two stability requirements does virtually every piece of equipment that uses an oscillator have?
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Amplitude and Frequency |
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What provides isolation between the oscillator and the load to prevent changes in the load from affecting the oscillator?
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Buffer |
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Which class of bias may oscillators use when a high efficiency is not required but distortion must be kept at a minimum?
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Class A |
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An amplifier can be made into a sine-wave oscillator by providing what through an RC network? |
Regenerative feedback |
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What is the reduction of amplitude in an oscillator circuit referred to as?
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Damping |
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What is the maintenance of oscillations in a circuit in the intervals between pulses of excitation energy?
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Flywheel effect |
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What is the property of a crystal by which mechanical forces produce electrical charges and, conversely, electrical chargesproduce mechanical forces?
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Piezoelectric effect |
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What is the frequency for which a crystal is ground referred to as?
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Natural resonant frequency |
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Commercially produced crystals range in Q from 5,000 to what?
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30,000 |
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In both tube and transistor oscillators, which circuit couples energy of the proper amount and of the correct phase from theoutput to the input circuit to sustain oscillations?
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Feedback |
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What is the process of transferring energy from a high-level point in a system to a low-level point in a system?
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Feedback |
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What is one of the requirements to sustain oscillations in an oscillator?
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Positive feedback |
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What is an oscillator in which DC power is supplied to the transistor through the tank circuit, or a portion of the tank circuitsaid to be?
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Series fed |
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Which type of oscillator receives its DC power for the transistor through a path separate and parallel to the tank circuitsaid to be?
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Shunt fed |
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What property of an oscillator is a measure of the degree to which a constant frequency output is approached?
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Frequency stability |
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What is a prime requirement for good frequency stability?
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Constant supply voltage |
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What property of a transistor oscillator indicates the amount by which the actual output amplitude varies from the desiredoutput amplitude?
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Amplitude stability |
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What is used to produce a sine-wave output of constant amplitude and of fairly constant frequency within the rf range? |
Armstrong oscillator |
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Which oscillator is very similar to the shunt-fed Hartley oscillator, except that two capacitors are used in the tank circuitinstead of a tapped coil?
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Colpitts |
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Which type of oscillator is usually used to produce an output which is highly stable and at a very precise frequency?
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Crystal-controlled |
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What do transmitters that require a very high degree of frequency stability use to maintain a constant crystal temperature?
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Temperature-controlled ovens |
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The amount of current that can safely pass through a crystal ranges from 50 to how many milliamperes?
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200 |
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The Q of a crystal may be more than how many times greater than that obtained with an equivalent electrical circuit?
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100 |
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Commercially produced crystals range in Q from 5,000 to 30,000 while some laboratory experiment crystals range inQ up to what?
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400,000 |
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Which type of oscillator will produce output pulses at a predetermined frequency for an indefinite period of time?
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Sinusoidal (sine-wave) |
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What is defined as a sinusoidal wave having a frequency that is a multiple of the fundamental frequency?
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Harmonics |
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What is a sine wave that is twice that fundamental frequency referred toas?
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Second harmonic |
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The second harmonic of a fundamental frequency has only what percent of the amplitude of the resonant frequency?
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20 |
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Frequency multipliers are special class C amplifiers that are biased at 3 to how many times the normal cutoff bias?
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10 |
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What decreases the loading effect on the oscillator by reducing the interaction (matching impedance) between the loadand the oscillator?
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Buffer amplifier |
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What is used to produce a sine-wave output of constant amplitude and fairly constant frequency?
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Hartley oscillator |
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Which type of waveform undergoes a pattern of changes that returns to its original pattern and repeats the same pattern ofchanges called?
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Periodic |
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Periodic waveforms are nonsinusoidal except for what?
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Sine wave |
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What is each completed pattern of a periodic waveform called? |
Cycle |
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What is the time called for one complete cycle?
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Pulse |
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What is the number of times in 1 second that the cycle repeats itself called?
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Pulse Repetition Frequency (PRF) |
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Rise time is defined as the time required for the voltage to build up from 10 percent to what percent of the maximum amplitudepoint?
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90 |
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What is the time required for the voltage to drop from 90 percent to 10 percent of the maximum amplitude point?
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Fall time |
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What is used to furnish deflection current in the electromagnetic cathode ray tube and is found in television and radar displaysystems?
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Trapezoidal wave |
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What is a very narrow pulse called?
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Trigger |
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What are Nonsinusoidal oscillators generally called?
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Relaxation oscillators |
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Which type of circuit is most often used to generate square or rectangularwaves?
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Multivibrator |
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Astable, monostable, along with what else are the three types of multivibrators?
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Bistable |
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Which type of multivibrator alternates between two different output voltage levels during the time it is on?
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Astable |
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Which type of multivibrator is used in computer logic systems and communication navigation equipment?
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Monostable |
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What are used in switching-circuit applications (computer logic operations) as counters, shift registers, clock pulse generators,and in memory circuits?
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Flip-flops |
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What is a special type of wave generator used to produce a narrow pulse,or trigger?
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Blocking oscillator |
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What gives the most rapid transient response without overshoot? |
Critical damping |
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What gives rapid transient response with overshoot caused by high or infiniteresistance? |
Underdamping |
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What is caused by very low resistance and gives a slow transient response? |
Overdamping |
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Which type of waveform do all radar sets, oscilloscopes, and computer circuitsuse? |
Sawtooth |
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Which type of device limits some part of a waveform from exceeding a specifiedvalue? |
Limiter |
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Limiting circuits are used primarily for wave shaping and what other applications?
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Circuit protection |
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Which circuit uses the same diode theory and voltage divider action as serieslimiters?
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Parallel-limiter |
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What clamps or restrains either the upper or lower extremity of a waveform to a fixed dc potential?
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Clamping circuit |
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Which type of circuits are widely used for coupling signals from one stageto another?
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Series RC |
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Timing circuits and circuits which require a particular shape or "spike" of voltage, may use what type of circuits?
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Shaping |
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What is a waveform other than a sine wave called?
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Complex wave |
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What is the sine wave which has the lowest frequency in the complex periodic wave referred to as? |
Fundamental frequency |
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Which term as applied to square waves, means that the waveform must be perfectly square? |
Pure |
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What is used as a waveshaping network in communications, radar, and computers? |
RC Integrator |
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Which type of circuit is used in timing or counting circuits in which the number of input pulses are represented by theoutput voltage?
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Positive-diode counter |
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Most step counters operate on a ratio of what or less?
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5 to 1 |
