Cathode Ray Oscilloscope MCQ || Cathode Ray Oscilloscope Questions and Answers

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.

1. Vertical Amplifier
2. 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.

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.

1. Vertical Amplifier
2. 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.

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.

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.

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.

1. Vertical Amplifier
2. 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.

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.

Answer.2. UJT

Explanation: 

A continuous sweep CRO using a UJT as a time base generator.  The UJT is used to produce the sweep.

Answer.3. Both High and low voltage

Explanation: 

Power Supply in CRO

There are two power supplies Generated in CRO

1. Negative High Voltage (HV) supply
2. 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.

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 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.

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.