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# How does oscilloscope work? How to use oscilloscope to measure voltage and current

Updated on November 14, 2016

## Working Principle of Cathode Ray Oscilloscope

Cathode Ray Oscilloscope is used in the electronics industry for the measurement of voltage and frequency of signals in the circuits. The CRO is also sometimes called as an eye for electronics engineer. It is an eye because it gives you the capability to see the waveform on the screen of CRO. Cathode ray oscilloscope basically has probes with positive and negative terminals that are connected in the circuit points where you want to measure voltage or frequency.

## Block diagram of Cathode Ray Oscilloscope

Figure above is the major block diagram of cathode ray oscilloscope. It mainly consists of electronic gun, deflection plates and screen. Electronic gun is made up of cathode with heated filament to produce electron beam. This electron beam passes through the deflection plates. There are two sets of deflection plates vertical and horizontal deflection plates. The deflection plates deflects the electron beam to form the waveform shape on the screen of CRO.

Vertical deflection plate deflects the beam in the y axis direction which tells about the amplitude of the waveform. The horizontal plates tell about the time domain on the x axis. Frequency can be measured by knowing the time period of the waveform on the x axis.

## Major parts of Cathode ray oscilloscope

Parts
Functions

Electron gun
produce electron beam
fine beam production
Deflection plates
helps in forming waveshape on the cro screen
waves like sinewave produced
Probes
probes are used to connect to the electronic circuit to be measured
positive and negative terminal of probes

## How to use cathode ray oscilloscope? Steps

1. Measure voltage of the signal by reading the measurements on the Y axis of the CRO screen.

2. Measure frequency of the signal by measuring the time period of the signal.

Phase pattern and other parameters can also be measured by the CRO. The two main measurement capabilities are notified above.

See results

## Working principle of Cathode Ray Oscilloscope Summary

1. CRO is used to measure voltage and frequency.
2. Signals to be measured are given to CRO by the probes.
3. the positive and negative terminal of probes connect the points on electronic circuit where measurement is needed to be done.
4. Phase patterns can also be measured with the help of lissajous pattern.

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