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What is a harmonic?

A harmonic of a particular frequency (the fundamental frequency f) is a frequency that is an integer multiple of the first one. For example:

if f = 125 MHz, the harmonics would be:

1st harmonic = 1f = 125 MHz

2nd harmonic = 2f = 250 MHz

3rd harmonic = 3f = 375 MHz

4th harmonic = 4f = 500 MHz

..... etc.

In the diagram below it can be seen that harmonics share common nodes.


Mathematically, the basic wave equation is:

<math> \mathit{v}=\mathit{f}\times \lambda </math>

v is the velocity of the wave in metres per second - a constant close to the speed of light for radio waves in the atmosphere.

f is the frequency of the wave - how many cycles pass a fixed point per second

<math> \lambda </math> is the wavelength of the wave in metres - the distance between two peaks of the wave.

So, as the frequency increases, the wavelength decreases - a doubling of frequency causes a halving of wavelength etc.

Where do harmonics come from?

Why are harmonics bad?

How do you get rid of harmonics?

External links

See also

Electronic Theory
Physical quantities Current * Gain * Impedance * Power * Q of a circuit * Radiated Power Measurement * Reactance* Resistivity * Resonance * Voltage
Components Baluns * Bipolar-Junction Transistors * Capacitors * Diodes * Inductors* Lasers * Microphones * Resistors * Transformers * Wire
Circuits Attenuators * Digital Signal Processing (DSP) * Dummy load * Filters * LC filters * Power Supply Design * Rectifier Circuits
Design Amplifier Design * Oscillator Design
Electromagnetic Waves Relative power (Decibels) * Harmonics * Interference and BPL