Question

The unknown frequency can be measured accurately using
1. Meggar
2. Voltmeter
3. Ammeter
4. CRO

Answer 1

Correct Answer - Option 4 : CRO

Explanation:

• CRO is a very versatile instrument in the laboratory for the measurement of voltage, current, frequency, and phase angle of any electrical quantity.
• A Lissajous figure is a pattern that is displayed on the screen when sinusoidal signals are applied to both horizontal & vertical deflection plates of CRO.
• These are used to measure the frequency of the given signals and the phase difference between the signals.
• From the shape of the Lissajous pattern displayed on the CRO screen information about relative phases of signals and the frequency ratio of signals can be determined.
• It is not used for precise measurement; it depends on the type of signal.
• If one frequency is an integral multiple (harmonic) of the other, the pattern will be steady. If not, the figure will not be stationary.