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harmonics in power

i was unable to understand what these harmonics are? plz help me regarding this

Reply to
dileepkumarladi
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When an electrical circuit does not draw a current from the supply that's equivalent to a resistive load, the current flow is non-sinusoidal.

Non-sinusoidal waveforms may be considered as a series of harmonics of the fundamental frequency (see Fourier).

That's where these harmonics come from.

Graham

Reply to
Eeyore

Non-resistive loads such as capacitors by themselves do not create harmonics.

As any waveform can be synthesised by adding harmonics of various amplitudes and phases, it follows that anything that causes a waveform to depart from a perfect sinewave will create harmonics, that is multiples of the fundamental frequency - 50 or 60 Hz.

A common example is the rectifier with a capacitive input filter, which draws a pulse from the supply at each voltage peak. If you put a scope on the mains you can see the blip caused by thousands of TV sets and computers all charging their filter capacitors together.

All the best Ian Macmillan

Reply to
Ian Macmillan 

--
That's not true, since if the load is linear, but reactive, and the
voltage across it is sinusoidal, the current waveform through the load
will also be sinusoidal.  Voltage and current will be out of phase
with each other, but no harmonics will be generated.
Reply to
John Fields

Same story with subharmonics?

Michael

Reply to
mrdarrett

I'm not familiar with any in this context.

Graham

Reply to
Eeyore

So if I've got a 50 kHz switcher, I don't have to worry about anything at 25 kHz, or 12.5 kHz?

MD

Reply to
mrdarrett

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