CATHODE RAY OSCILLOSCOPE Popular instrument to show time,  voltage both DC and AC. Shows Volts /  Time. Display waveform...
OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)
OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)    Electron gun
OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)    Deflection system
OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)    Fluorescent screen
OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)    Electron gun
OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)    Electron gun
OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)    Electron gun
OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)    Electron gun
OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)    Electron gun
OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)    Deflection system
VERTICAL ANDHORIZONTALDEFLECTION PLATES
OSCILLOSCOPE: CONTROL PANELPanel                     FunctionVOLTS/DIV                 Select the vertical deflection fact...
FREQUENCY AND PERIOD.   Frequency: measured in Hertz   Definition: number of times the signal    repeats itself in one s...
FREQUENCY AND PERIOD.   Period   Definition: the amount of time it takes    the signal to complete one cycle.
PHASE   1 cycle of a sine wave: 360⁰    Phase shift 90⁰
WAVEFORM MEASUREMENT (EXAMPLE)      Given:       volt/div   X: 50mV/div, Y: 200mV/div       time/div        1ms/div
WAVEFORM MEASUREMENT (EXAMPLE)      Peak to peak voltage :         Vpp = (volt/div) (no div peak to peak)         Vpp(X) ...
WAVEFORM MEASUREMENT (EXAMPLE)   Voltage peak:                0.4                       Vp( X )         0.2V             ...
WAVEFORM MEASUREMENT (EXAMPLE)   Time       T = (Time/div) ( no div in 1 cycle)            T(X) = (1 ms/div) ( 5 div) = 5...
WAVEFORM MEASUREMENT (EXAMPLE)
WAVEFORM MEASUREMENT (EXAMPLE)
CATHODE RAY OSCILLOSCOPE   When electrons hit the screen the phosphor is    excited and emits light.   Persistence. How ...
 This horizontal linear deflection is  produced by the Sweep generator. Sawtooth wave.   When the sweep signal returns...
CROS The display is made to appear  stationary. This controlled by your adjustment  settings. The eye sees a waveform....
 The signal is amplified by the vertical  amplifier, applied to the vertical plates. A portion of the vertical amp signa...
 The trigger can be based on 50 (60) Hz Provision is made for an external  trigger.                                     ...
CRO TUBE CONTROLS POWER on / off Scale Illumination Focus. Create spot on screen Intensity. Brightness (Don’t burn a ...
VERTICAL AMP Position on display Sensitivity of vertical amp Calibrated.  Cal fully clockwise.   Variable sensitivity. ...
VERTICAL AMP Position on display Sensitivity of vertical amp Calibrated.  Cal fully clockwise.   Variable sensitivity. ...
HORIZONTAL SWEEP   Sweep time / Div (or CM) Select    desired sweep rate, or admits external sig to    horiz amp. Sweep ...
TRIGGER       SET TO AUTO OR NORMAL Trigger selects timing of the beginning  of the Horizontal sweep. Slope selects trig...
VOLTS /DIV SWITCH Volts / Div Variable Fine adjustment these controls can have a Pull out switch  position. May be 5 ti...
VERTICAL MODE The operation of vertical deflection plates Chan 1 and Chan 2 can each operate  separately. Dual. Ch1 and...
TIME BASE   Main, Max, Min, delay.   Selects the sweep for the main mix or delay mode and    also X-Y switch Time/Div p...
OTHER Comp Test. Allows individual components to  be tested. Connect via banana jacks to test  resistors, capacitors, dio...
CONNECTIONS Vertical Input Horizontal Input External Trigger Cal. Out                     37
BANDWIDTH   A 10MHz CRO does not mean it will correctly    measure signals at 10MHz.   Vertical Amps are not so wide-ban...
EVERY CRO WILL BE DIFFERENT Many instruments made for specific work. Beam Finder push button Trace rotation Chan 1 Ver...
MINI EXERCISES Obtain a trace Brightness Focus Move trace up, down. Move trace side ways                         40
Upcoming SlideShare
Loading in...5
×

Emi cathode ray oscilloscope

3,341

Published on

Published in: Business, Technology
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
3,341
On Slideshare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
237
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

Transcript of "Emi cathode ray oscilloscope"

  1. 1. CATHODE RAY OSCILLOSCOPE Popular instrument to show time, voltage both DC and AC. Shows Volts / Time. Display waveforms. Spectrum scope shows volts to Frequency Cathode (-ve ) is heated, emits electrons, accelerated toward a (+ve) fluorescent screen. Intensity grid, Focus grid, Accelerating anode. (Electron gun) Horizontal deflection plates. Vertical deflection plates 1
  2. 2. OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)
  3. 3. OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)  Electron gun
  4. 4. OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)  Deflection system
  5. 5. OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)  Fluorescent screen
  6. 6. OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)  Electron gun
  7. 7. OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)  Electron gun
  8. 8. OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)  Electron gun
  9. 9. OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)  Electron gun
  10. 10. OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)  Electron gun
  11. 11. OSCILLOSCOPE: CATHODE-RAY TUBES (CRT)  Deflection system
  12. 12. VERTICAL ANDHORIZONTALDEFLECTION PLATES
  13. 13. OSCILLOSCOPE: CONTROL PANELPanel FunctionVOLTS/DIV Select the vertical deflection factor of the CRT displayTIME/DIV Select the horizontal deflection factor of the CRT displayINTEN (Intensity) The INTEN (intensity) control (sometimes called BRIGHTNESS) adjusts theControl brightness of the beam on the CRT. The control is rotated in a clockwise direction to increase the intensity of the beam and should be adjusted to a minimum brightness level that is comfortable for viewing.FOCUS and ASTIG The FOCUS control adjusts the beam size. The ASTIG (astigmatism) control(Astigmatism) Controls adjusts the beam shape. The FOCUS and ASTIG controls are adjusted together to produce a small, clearly defined circular dotTRACE ROTATION The TRACE ROTATION control allows for minor adjustments of the horizontalControl portion of the trace so that you can align it with the horizontal lines on the graticule.BEAM FINDER Control When pushed, the BEAM FINDER pulls the beam onto the screen so that you can use the horizontal and vertical POSITION controls to center the spot.Horizontal and Vertical The horizontal and vertical POSITION controls are used to position the trace.POSITION Controls Because the graticule is often drawn to represent a graph, some oscilloscopes have the positioning controls labeled to correspond to the X and Y axes of the graph. The X axis represents horizontal movement; the Y axis represents the vertical movement.AC-GDN-DC AC- Ac Signal GDN - grounding the signal DC- Dc Signal
  14. 14. FREQUENCY AND PERIOD.  Frequency: measured in Hertz  Definition: number of times the signal repeats itself in one second
  15. 15. FREQUENCY AND PERIOD.  Period  Definition: the amount of time it takes the signal to complete one cycle.
  16. 16. PHASE 1 cycle of a sine wave: 360⁰ Phase shift 90⁰
  17. 17. WAVEFORM MEASUREMENT (EXAMPLE)  Given: volt/div X: 50mV/div, Y: 200mV/div time/div 1ms/div
  18. 18. WAVEFORM MEASUREMENT (EXAMPLE)  Peak to peak voltage : Vpp = (volt/div) (no div peak to peak) Vpp(X) = (50mV/div) ( 8 div ) = 0.4 V Vpp(Y) = (200mV/div) ( 4 div ) = 0.8V
  19. 19. WAVEFORM MEASUREMENT (EXAMPLE) Voltage peak: 0.4 Vp( X ) 0.2V 2 Vpp Vp 0.8 2 Vp(Y ) 0.4V 2
  20. 20. WAVEFORM MEASUREMENT (EXAMPLE) Time T = (Time/div) ( no div in 1 cycle) T(X) = (1 ms/div) ( 5 div) = 5ms T(Y) = (1 ms/div) ( 5 div ) = 5ms
  21. 21. WAVEFORM MEASUREMENT (EXAMPLE)
  22. 22. WAVEFORM MEASUREMENT (EXAMPLE)
  23. 23. CATHODE RAY OSCILLOSCOPE When electrons hit the screen the phosphor is excited and emits light. Persistence. How long the display glows. May need to reduce ambient light for older instruments. Connect a signal to Vertical deflection plate. At same time a voltage that increases linearly with time (Ramp) is applied to the Horizontal deflection plates. 23
  24. 24.  This horizontal linear deflection is produced by the Sweep generator. Sawtooth wave. When the sweep signal returns to zero ie the end of the sweep, the beam flies back to the start position. The beam is cut off during the flyback time. 24
  25. 25. CROS The display is made to appear stationary. This controlled by your adjustment settings. The eye sees a waveform. X is <----> Horizontal Y is ^ Vertical Height of trace 25
  26. 26.  The signal is amplified by the vertical amplifier, applied to the vertical plates. A portion of the vertical amp signal is applied to the Sweep Trigger. The sweep trigger generates a pulse coincident with a selected point in the cycle of the trigger signal. This pulse turns on the sweep generator initiating the sawtooth wave form. The sawtooth wave is amplified by the horizontal amp and applied to the horizontal deflection plates 26
  27. 27.  The trigger can be based on 50 (60) Hz Provision is made for an external trigger. 27
  28. 28. CRO TUBE CONTROLS POWER on / off Scale Illumination Focus. Create spot on screen Intensity. Brightness (Don’t burn a spot on your screen) 28
  29. 29. VERTICAL AMP Position on display Sensitivity of vertical amp Calibrated. Cal fully clockwise. Variable sensitivity. Continuous range between calibrated steps. AC - DC - Gnd. Selects desired coupling for incoming signal, or grounds amp input. DC couples signal directly to amp. AC connects via a capacitor. (Blocks DC) Gnd = no signal. Gnd connects Y input to 0 volts. Checks position of 0v on screen. 29
  30. 30. VERTICAL AMP Position on display Sensitivity of vertical amp Calibrated. Cal fully clockwise. Variable sensitivity. Continuous range between calibrated steps. AC - DC - Gnd. Selects desired coupling for incoming signal, or grounds amp input. DC couples signal directly to amp. AC connects via a capacitor. (Blocks DC) Gnd = no signal. Gnd connects Y input to 0 volts. Checks position of 0v on screen. 30
  31. 31. HORIZONTAL SWEEP Sweep time / Div (or CM) Select desired sweep rate, or admits external sig to horiz amp. Sweep time / Cm Variable Continuously variable sweep rates. Cal is fully clockwise. Position Controls horizontal position of trace. Horizontal variable controls attenuation of signal applied to Horz amp through Ext Horiz connector. 31
  32. 32. TRIGGER SET TO AUTO OR NORMAL Trigger selects timing of the beginning of the Horizontal sweep. Slope selects trigger at +ve increasing or -ve decreasing portion of signal. Coupling Selects whether trigger is at a specific DC or AC level. Source: Int from Vertical Amp Ext from Ext Trig Input. Line AC line 50 (60) HZ 32
  33. 33. VOLTS /DIV SWITCH Volts / Div Variable Fine adjustment these controls can have a Pull out switch position. May be 5 times mag. 33
  34. 34. VERTICAL MODE The operation of vertical deflection plates Chan 1 and Chan 2 can each operate separately. Dual. Ch1 and Ch2 are swept alternatively. Why Dual? Used to measure input and Output signals of a device under test. Ch1 and Ch2 can be added 34
  35. 35. TIME BASE Main, Max, Min, delay. Selects the sweep for the main mix or delay mode and also X-Y switch Time/Div provides selection of sweep rates. Range of 0.1 Second, 50 to .1 mS, 50 to 0.1uS per div. Note 5,2,1, sequence. To determine a frequency use reciprocal. Frequency = 1/time period (50Hz = 1/20mS) Time period = 1/Frequency (number of div * ?ms/div. Eg 4div*5ms/div = 20 ms) 35
  36. 36. OTHER Comp Test. Allows individual components to be tested. Connect via banana jacks to test resistors, capacitors, diodes, transistors, etc Cal delivers calibrated voltage e.g. 2v p-p 1KHz square wave for setting scale. GND. Earth terminal of scope 36
  37. 37. CONNECTIONS Vertical Input Horizontal Input External Trigger Cal. Out 37
  38. 38. BANDWIDTH A 10MHz CRO does not mean it will correctly measure signals at 10MHz. Vertical Amps are not so wide-band as to amplify all signals. 10MHz is the 3dB point. A 10MHz signal of 1v will measure 0.707v on the screen. Clipping introduces odd order harmonics. A CRO operating near the max freq. will not show the harmonics and you think you are reading a clean signal. Square waves begin to look like sine waves. A rule of thumb is 5 times. To measure 2MHZ use a 10MHz CRO. 3 times is suitable for most Amateur work. For 7MHz. Times 3 = 21. Use a 20 MHz CRO. 38
  39. 39. EVERY CRO WILL BE DIFFERENT Many instruments made for specific work. Beam Finder push button Trace rotation Chan 1 Vertical input. During X-Y operation this is X axis (abscissa) Chan 2 Vertical input Chan 2. During X-Y this becomes ordinate input. 39
  40. 40. MINI EXERCISES Obtain a trace Brightness Focus Move trace up, down. Move trace side ways 40
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×