What is an Oscillator? Types and Function of Oscillator


You have heard of an oscillator, what you can say it is. One professor said that unless you are able to explain something to a layman to a level of understanding then you don’t know it. He believed that nothing known to man can be explained to the level of a child’s understanding. In this read, we are going to unravel all about oscillators. To help us in this, we will follow the formulae of what, why, how and finally the functions.

What is an Oscillator?

An oscillator is an electronic circuit that when a dc voltage is applied it generates a periodic time-varying waveform of the desired frequency. In simple terms, it’s a generator of desired waveforms. The distance example of an oscillator is a pendulum which when excited moves to and from a fixed point until the movement decays. One characteristic of an oscillator is that it has a uniform frequency of the waveform. To achieve this, there has to be a means of compensating the energy that is lost during oscillations. There are mechanical, hydraulic and electrical oscillators, however, in this post, we will look at electrical oscillators only as captured in our definition.

Also Read:

Basic Electrical

Static Electricity

How does Oscillator operate?

Crystal oscillators

To the big question now, how does it work? There are two main types of electronic oscillators namely; RLC and crystal ones. Crystal oscillator uses a special material such as quartz to which has the ability to get mechanically deformed when an electric field is applied. When voltage is applied to or near it, the electric field develops and causes electrostriction- this is expansion or shrinking of a material depending on polarity in the field. When the electric field is applied in opposite polarity the material responds accordingly resulting in vibration at the frequency of changing field. The crystal material has a piezoelectric effect, a phenomenon that causes a material to generate a voltage signal when mechanically deformed and this is how an oscillating signal is produced at the frequency of electric field change. For your information electrostriction and piezoelectric properties are natural characteristics that were discovered by our esteemed scientists.

RLC oscillators

Turning to RLC oscillators, where RLC in full stands for resistor, indictor and capacitor elements as building blocks of this circuit. The operating principle behind it cannot be explained without appreciating how the inductor and capacitor works. An inductor stores electric energy in a magnetic field and generally inhibits change of status quo, in that when the current starts to decrease it will come in and try to sustain this current by its stored energy until its depleted. The capacitor, on the other hand, is used to store charge in the electrostatic field (a region made of dielectric material and oppositely charged terminals.) The oscillating system consists of a capacitor in parallel with an inductor and a battery. The capacitor is charged by a battery, when the inductor is connected, capacitors discharge to the inductor and when drained, inductor discharges to a capacitor and the cycle continues over and over. Due to resistance of the wire, capacitor, inductor and a battery are there to compensate the lost charge, this ensures the capacitor is fully charged maintaining stable frequency.

The frequency at which an oscillator operates is known as resonant frequency and for the RLC circuit it is derived mathematically, for now just know bigger your inductor and capacitor the smaller the frequency.

Functions and Working of oscillators

Having discussed how oscillating signal is generated, is it of any use? I can confidently say, was it not important, you won’t be reading this piece, for it wouldn’t have been written. This signal is so vital in the electronic world that we cannot do without them. The guy behind a digital clock is an oscillator.  A quartz crystal is used to generate signals that make a timer, this clock you have it as a wristwatch, wall or table clock, the computer and phone clock among others. The square waves are taken to a counter then to display screen where you can read.  Another important clock is found in every digital device, it is used to synchronize every task performed by a microprocessor. It harmonizes and coordinates functions ensuring they are accomplished in a well-organized and orderly manner. Your phone and computer is a good example of clocked devices.

This post cannot end without mentioning, this one gadget. The world game-changer, a miracle I would call it-the radio is a device that revolutionized communication. A speaker can reach out to the whole world verbally using this device. When you start wondering how an oscillator is a radio, let me present to you the great challenge solved by an oscillator. An audio signal has a frequency of 330Htz and would only travel a few meters before it fades away. A high-frequency signal in the range of megahertz and gigahertz would travel thousands of meters away before fading. To take message signal in a far off listeners wirelessly, the audio signal was modulated by a high-frequency signal called a career, it becomes so effective that today FM stations are clearly heard using an average radio receiver. Where could this high frequency come from, the answer is an oscillator. At the receiving end, an oscillator produces a signal of the same frequency as the career to demodulate the signal. The setting of demodulating frequency is called tuning. An LC circuit is used, by adjusting usually the capacitance desired frequency is arrived at.

The functions that oscillators perform are many and diverse. In every scientific laboratory, there are oscilloscopes for generating and measuring signals that have greatly improved research. The same oscilloscope is used in the hospital to diagnose patients of conditions such as heartbeat. You will agree with me without a doubt that this device is so indispensable especially in today’s digital world.


It’s me believe this post has given you substantial information on this crucial electronic device and increased your knowledge base. While technological advancements are inevitable, be sure this device will continue to be miniaturized and more usage discovered but now that you are familiar with it. I trust you will be on par with this development and appreciate its arrival.

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