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700 matching questions

Question #261Basic Electricity and Electronics

The core of power supply transformer is laminated to

  1. decrease impedance
  2. increase impedance
  3. decrease eddy current losses ✓ Correct answer
  4. none of these

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Question #262Basic Electricity and Electronics

In a resonant circuit

  1. Xl = Xc ✓ Correct answer
  2. Xl > Xc
  3. Xl < Xc
  4. none of these
Explanation: At series resonance, inductive reactance equals capacitive reactance (XL = XC).

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Question #263Radio Theory and Communication Principles

When frequency of a carrier is varied according to modulation the result is

  1. frequency modulation ✓ Correct answer
  2. amplitude modulation
  3. product detection
  4. none of these

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Question #264Basic Electricity and Electronics

The phase relationship between the input and output of a common emitter circuit in degrees is

  1. 90
  2. 180
  3. 270
  4. 0 ✓ Correct answer

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Question #265Radio Theory and Communication Principles

The quartz crystal oscillator is known for its

  1. linearity
  2. stability ✓ Correct answer
  3. high output
  4. flexibility

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Question #266Radio Theory and Communication Principles

The effect of inter electrode capacitance of a triode is more predominant at

  1. HF
  2. VHF
  3. LF
  4. none of these ✓ Correct answer

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Question #267Radio Theory and Communication Principles

Which of the following is a characteristic of a liquid crystal display?

  1. It requires ambient or back lighting
  2. It offers a wide dynamic range
  3. It has a wide viewing angle
  4. All of these choices are correct ✓ Correct answer

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Question #268Radio Theory and Communication Principles

What is meant by the term MMIC?

  1. Multi Megabyte Integrated Circuit
  2. Monolithic Microwave Integrated Circuit ✓ Correct answer
  3. Military-specification Manufactured Integrated Circuit
  4. Mode Modulated Integrated Circuit

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Question #269Radio Theory and Communication Principles

What is a microprocessor?

  1. A low powered analog signal processor used as a microwave detector
  2. A miniature computer on a single integrated circuit chip ✓ Correct answer
  3. A microwave detector, amplifier, and local oscillator on a chip
  4. A low voltage amplifier used in a microwave transmitter modulator stage

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Question #270Basic Electricity and Electronics

What safety feature does a power-supply bleeder resistor provide?

  1. It acts as a fuse for excess voltage
  2. It discharges the filter capacitors ✓ Correct answer
  3. It removes shock hazards from the induction coils
  4. It eliminates ground-loop current

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Question #271Radio Theory and Communication Principles

What components are used in a power-supply filter network?

  1. Diodes
  2. Transformers and transistors
  3. Quartz crystals
  4. Capacitors and inductors ✓ Correct answer

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Question #272Basic Electricity and Electronics

What should be the minimum peak-inverse-voltage rating of the rectifier in a full-wave power supply?

  1. One-quarter the normal output voltage of the power supply
  2. Half the normal output voltage of the power supply
  3. Double the normal peak output voltage of the power supply ✓ Correct answer
  4. Equal to the normal output voltage of the power supply

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Question #273Basic Electricity and Electronics

What should be the approximate minimum peak-inverse-voltage rating of the rectifier in a half-wave power supply?

  1. One-half the normal peak output voltage of the power supply
  2. Half the normal output voltage of the power supply
  3. Equal to the normal output voltage of the power supply
  4. Two times the normal peak output voltage of the power supply ✓ Correct answer

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Question #274Radio Theory and Communication Principles

What should be the impedance of a low-pass filter as compared to the impedance of the transmission line into which it is inserted?

  1. Substantially higher
  2. About the same ✓ Correct answer
  3. Substantially lower
  4. Twice the transmission line impedance

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Question #275Radio Theory and Communication Principles

What is an advantage of a crystal controlled transmitter?

  1. Stable output frequency ✓ Correct answer
  2. Excellent modulation clarity
  3. Ease of switching between bands
  4. Ease of changing frequency

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Question #276Radio Theory and Communication Principles

What type of receiver is suitable for CW and SSB reception but does not require a mixer stage or an IF amplifier?

  1. A super-regenerative receiver
  2. A TRF receiver
  3. A super-heterodyne receiver
  4. A direct conversion receiver ✓ Correct answer

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Question #277Basic Electricity and Electronics

What type of circuit is used in many FM receivers to convert signals coming from the IF amplifier to audio?

  1. Product detector
  2. Phase inverter
  3. Mixer
  4. Discriminator ✓ Correct answer

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Question #278Basic Electricity and Electronics

What portion of the AC cycle is converted to DC by a half-wave rectifier?

  1. 90 degrees
  2. 180 degrees ✓ Correct answer
  3. 270 degrees
  4. 360 degrees

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Question #279Basic Electricity and Electronics

What portion of the AC cycle is converted to DC by a full-wave rectifier?

  1. 90 degrees
  2. 180 degrees
  3. 270 degrees
  4. 360 degrees ✓ Correct answer

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Question #280Basic Electricity and Electronics

What is the output waveform of an unfiltered full-wave rectifier connected to a resistive load?

  1. A series of DC pulses at twice the frequency of the AC input ✓ Correct answer
  2. A series of DC pulses at the same frequency as the AC input
  3. A sine wave at half the frequency of the AC input
  4. A steady DC voltage

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