How to read an Oscilloscope ?


What is an Oscilloscope?

The measuring instrument that measures electrical magnitudes and expresses the quantities they measure numerically or analogously is called an oscilloscope.

Most digital oscilloscopes have automatic measuring tools that simplify and speed up common measurement procedures. Thus, the reliability and accuracy of the measurement results have become even better. The manual measurement process described in this article will make the operation and control of automatic measurements more understandable.

When the 12 V AC voltage measured with a Voltmeter is Measured with the Oscilloscope, A Value of Approximately 16.97 V is read the reason of the different values ​​of the measuring instruments is Measuring the effective value of Ac, the Oscilloscope's Measuring the maximum value of Ac.

Although digital oscilloscopes are more expensive than other measuring instruments, it is easier to detect malfunctions in a system with  digital oscilloscopes. Because the outputs of television or more complex systems at certain points and floors are fixed and these outputs are specified point by point in the catalogs of the system. In the measurements made with the oscilloscope, there is a fault on the floor that gives a different output from the catalog.


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How to read an Oscilloscope ?

The x axis has the y axis on the output screen of the oscilloscope. The x axis shows the time, the y axis shows the voltage. Digital oscilloscopes enable us to determine the relationships between certain variables in electrical circuits.

Voltage Measurements

The amount of electrical potential between two points in a circuit is called voltage and its unit is expressed in volts. Alternating current, direct current and high frequency signals can be measured up to a maximum of 400 Volts with the oscilloscope.

The amplitude of the sign on the screen is measured on the Y (vertical) axis. The amplitude is first determined in squares on the screen. Then the actual value of the voltage is determined by multiplying the value indicated by the sign on the Volt / Div input attenuator commutator and the number of frames. At this time, the continuous amplitude adjustment knob, if any, must be turned to the end in the cal position or counterclockwise. If the probe weakens the amplitude; The attenuation coefficient should be multiplied and taken into account.
U = Number of Frames x (Volt / div) * Probe Coefficient



Period or Frequency Measurement

Each digital oscilloscope has a frequency measurement limit. Attention should be paid to this limit when measuring high frequencies. After selecting the digital oscilloscope suitable for the frequency value to be measured, an oscilloscope connection is made to the point to be measured. However, period is now measured in oscilloscopes instead of frequency. Period measurements are made on the X (horizontal) axis. The length of one period of the waveform in the X axis direction is determined by counting the squares. We get the value of the time / div button by multiplying the number of frames. However, if the probe weakens, the attenuation coefficient is multiplied and taken into account.
T = Number of Frames x (Time / div) * Probe Coefficient

What do oscilloscopes measure?

  • AC and DC voltage values
  • Waveforms of changing electrical magnitudes
  • Current passing through the circuit
  • Phase difference
  • Frequency
  • Characteristics of semiconductor elements such as diodes, transistors
  • Charge and discharge curves of the capacitor