# In CRO astigmatism is:

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In CRO astigmatism is: An additional focus control

## Related questions

The time base signal in Cathode Ray Oscilloscope (CRO) is  (1) A square wave signal (2) A sawtooth signal (3) A triangular wave signal (4) A sinusoidal signal

In a CRO which of the following is not a part of electron gun: (1) Cathode (2) Grid (3) Accelerating anode (4) X–Y plates

The Lissajous pattern on the screen of a CRO is an ellipse with major axis in quadrant 2 and quadrant 4. Then the phase difference between two signals Can be :  (A) 270° (B) 210° (C) 180° (D) 300°

Delay line is essential in a CRO, to ensure that (a) Vertical signal starts after the retrace period of sweep signal (b) The sweep reaches the horizontal plates before the desired signal under consideration (c) Initial part of signal to be observed is not lost (d) All of the above

The function of input attenuators in measuring instruments, like VTVM and CRO, is to (a) Increase the input impedance (b) Attenuate the frequency range (c) Attenuate the input signal amplitude without altering the frequency contents (d) Attenuate the input impedance

The sweep width in CRO is controlled by: -  a) Horizontal Gain Control b) Vertical Gain Control c) Accelerating-Anode Potential Control d) Focussing Anode Potential Control

An aquadog is used in a 'CRO' to collect -  a) Secondary emission electrons b) Primary emission electrons c) Both Primary and Secondary emission electrons d) None of the above

In a CRO, the quantity to be measured is applied across  (1) focusing electrodes (2) cathode (3) Y-plates (4) X-plates

In CRO, Lissajous pattern will be a straight line, if the two signals are of same frequency with a phase difference of (a) 0° (b) 180° (c) 360° (d) All of these

The two inputs of a CRO are fed with two stationary periodic signals. In the X-Y mode, the screen shows a figure Which changes from ellipse to circle and back to ellipse with its major axis changing orientation slowly and repeatedly. The following inference can be made from this  A) The signals are not sinusoidal ... but not equal C) The signals are sinusoidal with their frequencies very close but not equal D) There is a constant but small phase difference between the signals

Y –axis in a CRO normally represents

The Lissajous pattern observed on screen of CRO is a straight line inclined at 45° to x axis. If X–plate input is 2 sin ωt, the Y–plate input is (1) 2 sin ωt (2) 2 sin (ωt + 45°) (3) 2 sin (ωt – 45°) (4) 22 sin ωt + 45°)

The vertical deflection of an electron beam on the screen of a CRO is measured to be 8 mm. Now, the potential difference between the Y-plates is doubled, and simultaneously the pre-accelerating anode voltage is reduced to half of its previous value. Then, the vertical deflection of the beam on the screen would become (A) 64 mm (B) 32 mm (C) 8 mm (D) 1 mm

Consider the following statements with regard to Lissajous pattern on a CRO :  1. It is a stationary pattern on the CRO.  2. It is used for precise measurement of frequency of a voltage signal.  3. The ratio between frequencies of vertical and longitudinal voltage signals should be an integer to have a steady Lissajous pattern.  Which of the above statements is/are correct ?  (a) 1 only (b) 2 only (c) 3 only (d) 1, 2 and 3

CRO is used to measure ________. A. Amplitude B. Phase difference C. Frequency D. All of these

CRO is used to _________. A. produce frequency B. measure frequency C. produce phase difference D. none of these

Lissajous pattern obtained on a CRO screen is a circle. Frequency of two signals are   (a) Equal (b) Unequal (c) Zero (d) Infinity

List any four measure knobs on front panel on CRO.

List any two applications of CRO.

Draw block diagram of CRO. Write function of each block.

Two sinusoidal signals having the same amplitude and frequency are applied to the X and Y inputs of a CRO. The observed Lissajous figure is straight line. The phase shift between the two signals would be (1) Zero (2) 90 degrees (3) Either zero or 180 degrees (4) Either 90 degrees or 270 degrees

Lissajons figures asppear on CRO screen (a) when two sine waves of same frequency input signals. (b) depend on amplitude of two input signals. (c) depend on phase of two input signals. (d) used to measure harmonics.

Horizontal deflection plates of CRO are placed generally   (a) Horizontal (b) Vertical (c) Diagonal (d) (a) or (b)

A CRO cannot be used for direct measurement of   (a) Voltage (b) Current (c) Frequency (d) Power

The power in a 3-phase load is measured by two watt meters. If one watt meter reads zero, then the load power factor is (A) Zero (B) 0.5 (C ) 0.866 (D) unity

In a standard multimeter for measuring AC voltage, parameter of _____ voltage is measured

In dynamometer type of wattmeter, which of the coil is split up into two parts?

The type of instruments used mainly for standardizing instruments in laboratories is (a) Indicating instrument (b) Integrating instrument (c) Absolute instrument (d) Recording instrument

What will happen if a voltmeter is connected like an ammeter in series of the load ? (a) The meter will burn out. (b) The measurement will be too high. (c) The same current will flow as would have been with ammeter in circuit. (d) There will be almost no current in the circuit.

In a particular meter, the deflecting torque is directly proportional to the current flowing through it, the type of meter is (a) moving coil (b) moving iron (c) induction (d) electro-static

If a dynamometer wattmeter is connected in an ac circuit, the power indicated by the wattmeter will be (a) volt-ampere product (b) average power (c) peak power (d) instantaneous power

The material of hair spring used in measuring instruments is made of which of material of the following : (a) Copper (b) Bronze (c) Alnico (d) None of these

Eddy current damping is normally used in the instruments of (a) Induction type (b) Moving iron type (c) Permanent magnet moving coil type (d) Nothing can be said

A d.c. ampere-hour meter is rated at 5A, 250 V. The declared constant is 5 A sec/revolution. The constant in revolution/kwh will be (a) 2880 (b) 2680 (c) 2480 (d) 2280

The best method for measurement of temperatures of hot bodies radiating energy in the visible spectrum is (a) bolometer (b) optical pyrometer (c) thermocouple (d) thermopile

In a digital voltmeter, the oscillator frequency is 400 kHz, the ramp voltage falls from 8V to 0V in 20 m sec. The number of pulses counted by the counter is (a) 800 (b) 2000 (c) 4000 (d) 8000

In a galvanometer, the deflection becomes one half when the galvanometer is shunted by a 20 ohm resistor. The galvanometer resistance is

A wattmeter is connected as shown in the figure. The wattmeter reads

An ammeter has a current change of 0—5A and its internal resistance is 0.2 ohm. In order to Change the range to 0-25 A, wear need to add a resistance of  A) 0.8 ohm in series with the meter B) 1.0 ohm in series with the meter C) 0.04 ohm in parallel with the meter D) 0.05 ohm in parallel with the meter

A reading of 120 is obtained when a standard inductor was connected in the circuit of a Q-meter and the variable capacitor is adjusted to a value of 300 pF. A lossless capacitor of unknown value Cx is then connected in parallel with the variable capacitor and the same reading was obtained when the variable capacitor is readjusted to a value of 200 pF. The value of Cx in pF is  A) 100 B) 200 C) 300 D) 500

Weins bridge is used for measurement of frequency in the applied voltage waveform is measurement of frequency in the applied voltage waveform is   (A)sinusoidal (B) square (C) rectangular (D) triangular

The force required to move the pointer in an indicating instruments is

Integrating principle in the digital measurement is the conversion of   (a) Voltage to time (b) Voltage to frequency (c) Voltage to current (d) Current to voltage