E6D: Optical devices and toroids: vidicon and cathode-ray tube devices; charge-coupled devices (CCDs); liquid crystal displays (LCDs); toroids: permeability, core material, selecting, winding
How is the electron beam deflected in a vidicon?
By varying electromagnetic fields
By varying the beam voltage
By varying the bias voltage on the beam forming grids inside the tube
By varying the beam current
What is cathode ray tube (CRT) persistence?
The length of time the image remains on the screen after the beam is turned off
The time it takes for an image to appear after the electron beam is turned on
The relative brightness of the display under varying conditions of ambient light
The ability of the display to remain in focus under varying conditions
If a cathode ray tube (CRT) is designed to operate with an anode voltage of 25,000 volts, what will happen if the anode voltage is increased to 35,000 volts?
The image size will decrease
The image size will increase
The image will become larger and brighter
There will be no apparent change
Exceeding what design rating can cause a cathode ray tube (CRT) to generate X-rays?
The anode voltage
The heater voltage
The operating temperature
The operating frequency
Which of the following is true of a charge-coupled device (CCD)?
It samples an analog signal and passes it in stages from the input to the output
Its phase shift changes rapidly with frequency
It is a CMOS analog-to-digital converter
It is used in a battery charger circuit
What function does a charge-coupled device (CCD) serve in a modern video camera?
It stores photogenerated charges as signals corresponding to pixels
It generates the horizontal pulses needed for electron beam scanning
It focuses the light used to produce a pattern of electrical charges corresponding to the image
It combines audio and video information to produce a composite RF signal
What is a liquid-crystal display (LCD)?
A display that uses a crystalline liquid to change the way light is refracted
A modern replacement for a quartz crystal oscillator which displays its fundamental frequency
A frequency-determining unit for a transmitter or receiver
A display that uses a glowing liquid to remain brightly lit in dim light
What material property determines the inductance of a toroidal inductor with a 10-turn winding?
Core load current
What is the usable frequency range of inductors that use toroidal cores, assuming a correct selection of core material for the frequency being used?
From less than 20 Hz to approximately 300 MHz
From a few kHz to no more than 30 MHz
From approximately 1000 Hz to no more than 3000 kHz
From about 100 kHz to at least 1000 GHz
What is one important reason for using powdered-iron toroids rather than ferrite toroids in an inductor?
Powdered-iron toroids generally have better temperature stability
Powdered-iron toroids generally have greater initial permeabilities
Powdered-iron toroids generally require fewer turns to produce a given inductance value
Powdered-iron toroids have the highest power handling capacity
What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of transistorized HF amplifiers?
What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?
Toroidal cores contain most of the magnetic field within the core material
Toroidal cores make it easier to couple the magnetic energy into other components
Toroidal cores exhibit greater hysteresis
Toroidal cores have lower Q characteristics
How many turns will be required to produce a 1-mH inductor using a ferrite toroidal core that has an inductance index (A L) value of 523 millihenrys/1000 turns?
How many turns will be required to produce a 5-microhenry inductor using a powdered-iron toroidal core that has an inductance index (A L) value of 40 microhenrys/100 turns?
What type of CRT deflection is better when high-frequency waves are to be displayed on the screen?
Which is NOT true of a charge-coupled device (CCD)?
It is commonly used as an analog-to-digital converter
It uses a combination of analog and digital circuitry
It can be used to make an audio delay line
It samples and stores analog signals
What is the principle advantage of liquid-crystal display (LCD) devices over other types of display devices?
They consume less power
They can display changes instantly
They are visible in all light conditions
They can be easily interchanged with other display devices
What is one reason for using ferrite toroids rather than powdered-iron toroids in an inductor?
Ferrite toroids generally require fewer turns to produce a given inductance value
Ferrite toroids generally have lower initial permeabilities
Ferrite toroids generally have better temperature stability
Ferrite toroids are easier to use with surface mount technology
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