# How an oscillator creates electromagnetic waves

• chef99
In summary: I meant to say "capacitor" sorry. Anyway, in summary, an oscillator creates an electromagnetic wave that travels through space.
chef99

## Homework Statement

A cell phone sends and receives electromagnetic waves in the microwave frequency range.
Explain the physics of how an oscillator creates these waves.

n/a

## The Attempt at a Solution

An electromagnetic wave is created by the functioning of the oscillator. A simple oscillator generally consists of an inductor, which stores energy as a magnetic field and a capacitator, which stores energy as an electric static field. Connect a charged capacitator to a circuit and it will discharge through the inductor. This will cause the inductor to create a magnetic field. The inductor will try and maintain the current, and in doing so charges the other plate of the capacitator. By the time the inductor’s magnetic field has collapsed, the capacitator has been charged but with the opposite polarity. The capacitator will again discharge through the inductor, again creating a magnetic field, but this time the current is moving in the opposite direction through the circuit. Repeating this process creates an oscillating current, which gets transmitted into the antenna of the transmitter. The accelerating oscillating charges have a changing electric field, which creates a changing a varying magnetic field, which creates a varying electric field. This pattern continues on in this order. This interaction between the electric and magnetic fields, perpendicular to each other, is what creates an electromagnetic wave that travels through space.

I understand this is a bit long so thanks for taking the time to read it. The reason it is so long is because the question says to explain the "physics" of it so I think I have to be pretty technical. I think I have explained it properly but if anyone sees otherwise I would value the feedback.

Your explanation, in your own words, manages to convey the general idea. A minor correction is that the word is "capacitor" not "capacitator".

kuruman said:
Your explanation, in your own words, manages to convey the general idea. A minor correction is that the word is "capacitor" not "capacitator".

Oh jeez, thanks for catching that.

## 1. How does an oscillator create electromagnetic waves?

An oscillator is a device that generates an alternating current (AC) signal, which is a form of electrical energy that constantly changes direction. This changing current produces a magnetic field, which in turn creates an electric field. Together, these fields create electromagnetic waves that propagate through space at the speed of light.

## 2. What type of oscillator is used to create electromagnetic waves?

The most commonly used type of oscillator for creating electromagnetic waves is a radio frequency (RF) oscillator. This type of oscillator generates AC signals at radio frequencies, which are typically in the range of 3 kHz to 300 GHz.

## 3. How does an oscillator generate a continuous stream of electromagnetic waves?

An oscillator is designed to maintain a constant output frequency by using a feedback loop. The AC signal produced by the oscillator is fed back into the circuit, where it is compared to a reference signal. Any deviations from the desired frequency are corrected, resulting in a continuous stream of electromagnetic waves.

## 4. Can an oscillator be used to generate different types of electromagnetic waves?

Yes, an oscillator can be designed to generate different types of electromagnetic waves by varying its frequency and waveform. For example, a square wave oscillator can produce square-shaped electromagnetic waves, while a sinusoidal oscillator can generate sinusoidal waves.

## 5. What is the role of an antenna in the creation of electromagnetic waves by an oscillator?

An antenna is used to convert the electrical energy from the oscillator into electromagnetic waves that can travel through space. It is designed to efficiently radiate the electromagnetic waves into the surrounding environment, allowing them to be received by other devices or systems.

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