Cathode Ray Oscilloscope (CRO) Working and Applications

A Cathode Ray Oscilloscope is a special type of device. It can display the amplitude of an electrical signal as a function of time.

Introduction of CRO

We call this device also as CRO in short. A CRO is a very useful device.  We mainly use this device for displaying, measuring and analyzing different electrical signals.

Working Principle of CRO

The working principle of a cathode ray oscilloscope is simple enough. It depends on the movement of an electron beam due to the electrostatic force. When an electron beam strikes a phosphor surface, it creates a glowing spot on it. A CRO applies the electrostatic force on the electron beam from two perpendicular directions. That means we apply one force along the X-axis and another along the Y-axis. The spot on the phosphor screen moves due to the effect of these two mutually perpendicular electrostatic forces. It moves to create the required waveform of the input signal.

cathode ray oscilloscope

Vertical Plates

The electron beam deflects along the X-axis due to a periodic electrostatic force applied at a constant rate. More clearly to say, the glowing spot moves along the X-axis on the phosphor screen. It moves at a constant speed with constant intervals.

Horizontal Plates

In addition to that, we apply the electrostatic force on the electron beam along the Y-axis. This force is proportional to the amplitude of the signal. Hence, the electron beam deflects up and down along the Y-axis.

A Cathode Ray Oscilloscope is a very sensitive device. It can analysis or display the event occurs in the signal even within a period of few microseconds or nanoseconds.

A CRO is a voltage-operated device. But we know that transducers can convert currents, strains, accelerations, pressures, or many other quantities into the voltage. Therefore with the help of this device, we can analyze these quantities.

We can also measure frequencies, by analyzing the waveform of an alternating signal. A CRO can measure frequencies up to a few GHz. It is also able to measure very low frequency such as up to 20Hz.

Some modern CROs consist of digital multimeters and counters. These types of oscilloscope give direct readings of amplitude, wavelength, frequency, etc. Obviously, these oscilloscopes do that along with a display of the waveform.

In some other variants of CROs, there is a microprocessor-based controller provided in it. These CROs can calculate the rise time, pulse width of the waveform. These also display the same along with the waveform on the screen.

Application of Cathode Ray Oscilloscope

There are uncountable applications of Cathode Ray Oscilloscopes. It is next to impossible to provide a complete list of such applications here.

  1. The CRO traces the actual waveform of an electrical signal.
  2. Also, it determines the amplitude of the waveform.
  3. It can compare the phases and frequencies of electrical signals.
  4. Cathode Ray Oscilloscopes can also measure capacitance and inductance values.
  5. One very common application of cathode ray oscilloscope is on the television.
  6. A CRO can display the B-H curve for the hysteresis loop.
  7. Also, CROs have wide application in the medical field. For displaying heartbeat rates, nervous reactions, etc. Medical practitioners use CROs for purposes.
  8. We can also use this device to check the defective components in an electrical circuit.

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