- Describe the structure of a cathode-ray oscilloscope
- What is the function of filament?
The filament, a tiny tungsten which is heated by current, gives off electrons due to heat generated by an electric current.
- What is the function of grid?
The grid controls the brightness. When the grid is made negative it pushes back some electrons so that fewer of them reach the screen.
- What is the function of anode?
The anode accelerate electrons toward the screen.
- What is the function of the electron-gun?
The electron gun makes a narrow beam of electrons. Its cathode gives off electrons and the anode accelerate them.
- What is the function of X-plates?
The X-plates are uses to move the electrons beam across the x-axis of the screen.
- What is the function of Y-plates?
The Y-pates are used to move the electrons beam up and down the screen along the y-axis of the screen. When an AC signal is placed at the Y-plates, they move the beam up and down resulting in a moving spot on the screen. So, by these plates we can dray the variations of an electrical signal with respect to time.
- What is the function of fluorescent screen?
The screen is coated in a fluorescent material. It shows a bright spot where the electron beams strikes it. The screen also is divide into 1 cm squares. Each square is called a division. The horizontal divisions represents units of time set by the time base and the vertical divisions represents the gain in units of volts set by the
gain-control of the oscilloscope.
- What is the function of time-base?
The time base changes the voltage across the x-plates so that the beam moves from left to right across the screen. When the beam is at the right side of the screen, the time-base circuits turn off the beam and starts at left side. This process is repeated many times in a second. The number of repetition is called the frequency of the time base.
- What can be measured by an oscilloscope?
An oscilloscope can be used to measure the (1) the peak voltage of an AC signal and (2) the period of the AC signal.
- Explain how to use an oscilloscope to measure the voltage of an AC signal and its period.
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