A cathode-ray tube is a device that uses a beam of electrons in order to produce an image on a screen. The Role of CRT is to Emit Electron. The heart of the major component of the oscilloscope is the cathode ray tube (CRT). The rest of the CRO consists of circuitry to operate the CRT.
2. The delay line used in a CRO to ______
Boost the signal
Distort the signal
Provide signal delay
For stability
Answer.3. Provide signal delay
Explanation:
A delay line is placed between the output of the vertical amplifier and the y input of the cathode ray tube, to delay the incoming unknown signals.
The purpose of the delay line is to synchronize unknown signals with sweep signals such that the complete signal portion will be displayed without any loss.
3. Delay line is essential in a CRO, to ensure that
Vertical signal starts after the retrace period of sweep signal
The sweep reaches the horizontal plates before the desired signal under consideration
Initial part of signal to be observed is not lost
All of the above
Answer.3. Initial part of signal to be observed is not lost
Explanation:
A delay line is placed between the output of the vertical amplifier and the y input of the cathode ray tube, to delay the incoming unknown signals.
The purpose of the delay line is to synchronize unknown signals with sweep signals such that the complete signal portion will be displayed without any loss.
4. In cathode Ray oscilloscope in vertical amplifier ______ is used in amplifier stage.
JFET
BJT
Diode
Zener Diode
Answer.2. BJT
Explanation:
The vertical amplifier consists of several stages, with fixed overall sensitivity or gain expressed in V/div.
The advantage of fixed gain is that the amplifier can be more easily designed to meet the requirements of stability and Bandwidth.
The vertical amplifier is kept within its signal handling capability by proper selection of the input attenuator switch.
The first element of the pre-amplifier is the input stage, often consisting of a FET source follower whose high input impedance isolates the amplifier from the attenuator.
This FET input stage is followed by a BJT emitter follower, to match the medium impedance of FET output with the low impedance input of the phase inverter.
5. Input signals in Cathode ray tube are amplified using _______
Rectifier
Amplifier
Oscillator
Op-amp
Answer.2. Amplifier
Explanation:
Input signals in Cathode ray tube are amplified using Amplifier.
Basically two types of amplifier is used in Cathod ray tube.
Vertical Amplifier
Horizontal Amplifier
Horizontal Amplifier − It amplifies the sawtooth signal and then connects it to the horizontal deflection plates of CRT.
Vertical Amplifier − It amplifies the input signal, which is to be displayed on the screen of CRT.
6. ______ amplifies the sawtooth signal in the Cathode Ray tube.
Vertical Amplifier
Horizontal Amplifier
Both Vertical and Horizontal Amplifier
None of the above
Answer.2. Horizontal Amplifier
Explanation:
Input signals in Cathode ray tube are amplified using Amplifier.
Basically two types of amplifier is used in Cathod ray tube.
Vertical Amplifier
Horizontal Amplifier
Vertical Amplifier − It amplifies the input signal, which is to be displayed on the screen of CRT.
Horizontal Amplifier − It amplifies the sawtooth signal and then connects it to the horizontal deflection plates of CRT.
The saw-tooth voltage is fed to the horizontal amplifier which includes a phase inverter and produces two simultaneous output waveforms: a positive-going saw-tooth (run-up) and a negative-going saw-tooth (run-down).
The positive-going saw-tooth is applied to the right-hand horizontal deflection plate of the CRT, and the negative-going saw-tooth ” to the left-hand horizontal deflection plate.
The horizontal amplifier basically serves two purposes:
1. When the oscilloscope is being used in the ordinary mode of operation to display a signal applied to the vertical input, the horizontal amplifier will amplify the sweep generator output.
2. When the oscilloscope is being used in the X-Y mode, the signal applied to the horizontal input terminal will be amplified by the horizontal amplifier.
7. Phase inverter is used in an amplifier in the CRO because ________
Phase inversion is needed
No phase inversion is needed
It is needed to operate a push-pull
It provides voltage stability
Answer.3. It is needed to operate a push-pull
Explanation:
This phase inverter in CRO provides two antiphase output signals which are required to operate the push-pull output amplifier.
The push-pull output stage delivers equal signal voltages of opposite polarity to the vertical plates of the CRT.
The advantages of push-pull operation in CRO are similar to those obtained from push-pull operation in other applications; better hum voltage cancellation from the source or power supply (i.e. d, even harmonic suppression, especially the large 2nd harmonic is canceled out, and greater power output per tube as a result of even harmonic cancellation.
In addition, the number of defocusing and non-linear effects are reduced, because neither plate is at ground potential.
8. The Amplifier stage in Cathode Ray Tube is ___________
Half band
Full band
Wide band
Narrow band
Answer.3. Wideband
Explanation:
The Amplifier stage in Cathode Ray Tube is Wide Band.
In the case of a wide-band oscilloscope tube that it should have as great a deflection sensitivity as possible (if necessary, at the expense of other qualities). The vertical amplifier is the principal factor in determining the sensitivity and bandwidth of an oscilloscope.
The vertical amplifier is a wide band amplifier used to amplify signals in the vertical section. Delay time is used to delay the signal for some time in the vertical sections.
9. In cathode Ray tube Input stage in the amplifier consists of ___________
Oscillator
Attenuator
Rectifier
op-amp
Answer.2. Attenuator
Explanation:
Input signals in the Cathode ray tube are amplified using Amplifier. The amplifier stage of a Cathode Ray Tube essentially consists of an attenuator stage.
Basically, two types of amplifiers are used in the Cathode ray tube.
Vertical Amplifier
Horizontal Amplifier
The first element of the pre-amplifier is the input stage, often consisting of a FET source follower whose high input impedance isolates the amplifier from the attenuator. This FET input stage is followed by a BJT emitter follower, to match the medium impedance of FET output with the low impedance input of the phase inverter.
10. The vertical amplifier is a _______ amplifier.
Half band
Full band
Wideband
Narrow band
Answer.3. Wideband
Explanation:
The Amplifier stage in Cathode Ray Tube is Wide Band.
In the case of a wide-band oscilloscope tube that it should have as great a deflection sensitivity as possible (if necessary, at the expense of other qualities). The vertical amplifier is the principal factor in determining the sensitivity and bandwidth of an oscilloscope.
The vertical amplifier is a wideband amplifier used to amplify signals in the vertical section. Delay time is used to delay the signal for some time in the vertical sections.
11. A continuous sweep CRO uses a ______ as a time base generator.
BJT
UJT
FET
JFET
Answer.2. UJT
Explanation:
A continuous sweep CRO using a UJT as a time base generator. The UJT is used to produce the sweep.
12. The power supply generated in CRO is
High voltage only
Low Voltage only
Both High and low voltage
Medium voltage
Answer.3. Both High and low voltage
Explanation:
Power Supply in CRO
There are two power supplies Generated in CRO
Negative High Voltage (HV) supply
Positive Low Voltage (LV) supply
The +ve volt supply is from + 300 to 400 V.
The -ve high voltage supply is from – 1000 to – 1500 V.
This voltage is passed through a bleeder resistor at a few mA. The intermediate voltages are obtained from the bleeder resistor for intensity, focus, and positioning controls.
13. What are the advantages of Negative High Voltage (HV) supply in CRO?
Shock Protection
No need of coupling Capacitor
Less insulation is Needed
All of the above
Answer.4. All of the above
Explanation:
Advantages of using -ve HV Supply
(i) The accelerating anodes and the deflection plates are close to ground potential. The ground potential protects the operator from HV shocks when making connections to the plates.
(ii) The deflection voltages are measured wrt the ground, therefore HV blocking or coupling capacitors are not needed, but low voltage rating capacitors can be used for connecting the HV supply to the vertical and horizontal amplifiers.
(iii) Less insulation is needed between positioning controls and chassis.
14. To display voice or music signal _____ is used in CRO.
Triggered Sweep
Continuous Sweep
Frequency Sweep
Any of the above
Answer.2. Continuous Sweep
Explanation:
The continuous sweep is of limited use in displaying periodic signals of constant frequency and amplitude. When attempting to display voice or music signals, the pattern falls in and out of sync as the frequency and amplitude of the music vary resulting in an unstable display.
A triggered sweep can display such signals, and those of short duration, e.g. narrow pulses. In triggered mode, the input signal is used to generate substantial pulses that trigger the sweep. Thus ensuring that the sweep is always in step with the signal that drives it.
15. ______ is used in CRO so that the input signal and the sweep frequency can be synchronized.
Time Sweep
Phase Inverter
Attenuator
Triggered Circuit
Answer.4. Triggered Circuit
Explanation:
Trigger Circuit is used to convert the incoming signal into trigger pulses so that the input signal and the sweep frequency can be synchronized.
The trigger circuit is activated by signals of a variety of shapes and amplitudes, which are converted to trigger pulses of uniform amplitude for the precision sweep operation.
If the trigger level is set too low, the trigger generator will not operate.
On the other hand, if the level is too high, the UJT may conduct for too long and part of the leading edge of the input signal may be lost.
