Use of cro for frequency measurement, Electrical Engineering

Assignment Help:

Q. Explain the use of CRO for frequency measurement.

 

Measurement of frequency: The frequency of the periodic signals is easily measured with a CRO. The frequency of a signal to be measured is compared with a known frequency. A sinusoidal voltage of unknown frequency (the frequency which is to be measured) is applied to the vertical plates. If the ratio of two frequencies (f and f) is an integer, a clearly defined and distinctive pattern appears on the screen. These patterns are known as Lissajous pattern.

Let us assume that two sinusoidal voltages applied to the vertical and horizontal plates of the CRO have equal frequency and same phase and let that voltages applied to the plates be given as voltage at vertical plate.

When the frequency of the two voltages is not equal then to obtain the Lissajous pattern is not simple. Lissajous pattern may be classified into two general categories, the closed and the open Lissajous patterns. A closed Lissajous pattern is continuous and has no break it has no free ends as shown in fig. The open patterns are simply steady traces and have free ends. 

The ratio of vertical to horizontal frequencies of closed Lissajous patterns can be obtained by counting the number of positive vertical peaks and dividing it by number of positive horizontal peaks and is given by the formulae.

Lissajous patterns are used for accurate measurement of frequency of a waveform. The signal or the waveform, whose frequency is to be measured, is applied to the vertical deflection plates the CRO, an accurately calibrated standard frequency source is used to supply voltage to the horizontal deflection plate with the internal sweep generator switched off.

 


Related Discussions:- Use of cro for frequency measurement

Switching characteristics - power semiconductor devices, Switching charact...

Switching characteristics When  a positive signal  is applied GTO starts  conducting before  initiation of  conduction anode  current  is zero  and anode to cathode voltage Va

Determine the inductor current, Q. In a GLC parallel circuit excited by a c...

Q. In a GLC parallel circuit excited by a current source i(t), for G = 0.5S, L = 3H, and C = 0.5 F, determine i(t) if the inductor current iL(t) = 12e -0.5t .

What do you mean by number systems, Q. What do you mean by Number Systems? ...

Q. What do you mean by Number Systems? The Digital circuits are inherently binary in nature, but numerous types of representations of numerical data are in use. The represen

Calculate armature voltage, Question: A DC, separately excited motor is...

Question: A DC, separately excited motor is supplied from a 240-V source. When the motor is unloaded, it draws 1A of current from the source. When the motor is loaded, it draws

Define magnetic field, Define Magnetic field The area around a magnet i...

Define Magnetic field The area around a magnet is known as the magnetic field and it is in this area that the effects of the magnetic force formed by the magnet can be detected

Zener diode, where is a zener diode used in a car

where is a zener diode used in a car

Find fmax for circuit, Q. (a) An audio amplifier with R i = 10 k, R o ...

Q. (a) An audio amplifier with R i = 10 k, R o = 0, and ¯A(ω), as shown in Figure (a), is used in the circuit shown in Figure with R S = 1 k,R L = 16 , and C = 0.2 µF. Sk

Determine the overall power factor, A three-phase, wye-connected, cylindric...

A three-phase, wye-connected, cylindrical-rotor, synchronous motor, with negligible armature resistance and a synchronous reactance of 1.27 per phase, is connected in parallel wit

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd