cathode ray oscilloscope
- 1. REPORTED BY: Name: Prapti borthakur POWIET
- 2. Introduction How a CRO looks like? Block diagram of CRO Cathode ray tube Internal structure of CRT Working of CRT Applications Uses
- 3. The cathode ray oscilloscope is most versatile laboratory instrument. It is used for studying waveshapes of alternating currents and voltages as well as for measurement of voltage,amplitude,frequency,phase etc. CRO is an electronic display device used to convert electrical signals to visual signal.
- 6. WORKING OF CRO A CRO employes a Cathode ray tube, which acts as the heart of the oscilloscope. The CRT generates the electron beam which are accelerated to a high velocity and brought to focus on a fluorescent screen.This screen produces a visible spot where the electron beam strikes it. For this tasks various electricals signals and voltages are required ,which are provided by the power supply circuit of the oscilloscope. Horizontal & vertical deflection plates are fitted between the electron gun and the screen so these can deflect the beam according to the input signal. To deflect the electron beam on the screen on X-axis with constant rate a time base generator is provided.
- 7. Low voltage supply is required for the heater of the electron gun to generate the electron beam and high voltage is required for the cathode ray tube to accelerate the beam. The signal to be viewed is supplied to the vertical deflection plate through the vertical amplifier,so that it can amplify the signal to a level that will provide usuable deflection of the electron beam As the electron beam is deflected in X-axis & Y-axis, a triggering circuit is provided for synchronizing these two types of deflections starts at the same point of the input vertical signal each time it sweeps.
- 8. The cathode ray tube is the heart of the cathode ray osciiloscope. The main parts of CRT are: 1.Electron gun assembly 2.Deflection plate assembly 3.Fluorescent screen 4.Glass body & base
- 11. Cathode: Release the electron when heated by heater
- 12. Grid: 1.The grid is connected to a negative potential 2.The more negative this potential,the more electron will be repelled from the grid and fewer electron will reach the anode and the screen. 3.The number of electrons reaching the screen determines the brightness of the light.Hence the negative potential of the grid can be used as a brightness control
- 13. Focusing anode and accelerating anode: The anode at positive potential accelerates the electron and the electrons are focused into a fine beam so they pass through the anode
- 14. Y-plates: The Y-plates will cause deflection in the vertical direction when a voltage is applied across them.
- 15. X-plates:The X-plates will cause deflection in the horizontal d
- 16. Voltage measurement Current measurement Examination of waveform Measurement of phase & frequency
- 17. In laboratory,CRO can be used as: • It can display different types of waveforms • It can measure short time intervals • In voltmeter,it can measure potential difference