S.SESHA PHANINDHRA
12705A0425 II BTECH ECE-B
ANNAMACHARYA INSTITUTE OF TECHNOLOGY AND SCIENCES RAJAMPET
(AN AUTONOMOUS INSTITUTION)
CONTENTS• INVENTION OF CRO• DEFINITION OF CRO• BLOCK DIAGRAM OF CRO• EXPLANATION OF EACH BLOCK• NECESSITY OF TIME BASE VOLTAGE• FUNCTIONS OF VARIOUS CONTROL TERMINALS OF CRO• SPECIFICATIONS OF CRO• MEASUREMENT OF VARIOUS PARAMETERS USING CRO• APPLICATIONS OF CRO• CONCLUSION
DEFINITION OF CRO:• It is an electronic equipment that provides visual images of varying electrical quantities
EXPLANATION OF EACH BLOCKCathode Ray Tube (CRT):• The heart of the CRO is CRT• It produces the visual pattern on its screenVertical amplifier:• It amplifies the input signalTime base generator:• It is used to deflect the beam in the horizontal section
Horizontal amplifier:• It amplifies the sawtooth voltageTrigger circuit:• The trigger circuit controls the time base generator and horizontal amplifier
Delay line:• It is used to delay the signal for sometime in the vertical sections
NECESSITY OF TIME BASE VOLTAGE:• If sweep voltage is not applied then only a vertical line will be displayed
FUNCTIONS OF VARIOUS CONTROL TERMINALS OF CRO1.Time/division:• This adjusts the horizontal gain that is width of the pattern.
2.Volts/division:• This adjusts the vertical gain that is the height of the pattern.
3.Coupling:• It decides the mode of input coupling.
4.Level:• This is for selecting the amplitude points on trigger signal at which the time base generator starts the sweep.
5. Horizontal position control:• It is for moving the pattern left to right and right to left on the screen
6.Vertical position control:• It is used for moving the pattern up and down on the screen
7. Focus:• It is for sharp trace on the screen.8. Intensity:• It is for correct brightness of the trace on the screen.
SPECIFICATIONS OF CRO1. Vertical amplifier:• Sensitivity:5m volts/divi to 20 volts/divi• Accuracy: + or – 3%• Bandwidth: 0 to 20M hz , dc coupling 0.5 hz to 20M hz , ac coupling
2.Horizontal amplifier:• Bandwidth:0 to 2Mhz• Input impedance:1Mohm/50pf
3.Time base:• Sweep ranges:0.1microsecond/div to0.5sec/div
• Accuracy:+or-5%4.Triggering:• Polarity:positive or negative• Max trigger input:250v• Input impedance:1Mohm/30pf
MEASUREMENT OF VARIOUS PARAMETERS USING CRO
1.Voltage:• No. of verticaldivisions*volts/div2.Time period:• No. of horizontal divisions*time/div3.Frequency:• f=1/Time period
4.Phase:• By using lissajous patterns phase can be determined5.Modulation index:• m = (Y2-Y1)/(Y2+Y1)• where Y1 is the min voltage level of modulated signal and
• Y2 is the max voltage level of modulated signal6.Pulse parameters:• Rise time,fall time,pulse width and amplitude of pulse can also be determined
APPLICATIONS OF CRO• CRO is extensively used for trouble shooting• Examination of waveform• Voltage measurement• Current measurement• Measurement of time interval• Frequency measurement• Modulation index measurement• Pulse measurement• Radio applications• Scientific applications• Engineering applications
• CONCLUSION• Invention and development of CRO has became a very advantageous in the electronics field as well as in the communication field• It is a very useful and versatile electronic laboratory equipment as it is used for measurement of various parameters and as it is having a wide variety of applications
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