# How is sinusoidal current generated?

## Main Question or Discussion Point

I'm delving into AC as well as attempting to understand the various wave forms used in electrical engineering, and I am curious how engineers are able to generate current which alternates in a sinusoidal manner. What specific phenomena allows us to achieve this? Is it a special circuit, or does it have to do purely with the electromagnetics of a current generator?

Thanks!!

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Doug Huffman
Gold Member
Circular function relative motion between magnetic flux and conductor.

davenn
Gold Member
2019 Award
Circular function relative motion between magnetic flux and conductor.
is the usual mechanical way ( power generating station, alternator in a car)

it can also be done purely electronically
say a Wien Bridge oscillator

Dave

Doug Huffman
Gold Member
HIgh current inverters are problematic. In my industry we used zero to adjustable low frequency stepping resistors to roughly simulate 3-phase 'alternating' current.

berkeman
Mentor
I'm delving into AC as well as attempting to understand the various wave forms used in electrical engineering, and I am curious how engineers are able to generate current which alternates in a sinusoidal manner. What specific phenomena allows us to achieve this? Is it a special circuit, or does it have to do purely with the electromagnetics of a current generator?

Thanks!!
You can also use a Waveform Generator IC to make sine, triangle and square waves (as well as other waveforms). That is how basic signal generator equipment works:

:-)

phinds
Gold Member
2019 Award
I'm delving into AC as well as attempting to understand the various wave forms used in electrical engineering, and I am curious how engineers are able to generate current which alternates in a sinusoidal manner. What specific phenomena allows us to achieve this? Is it a special circuit, or does it have to do purely with the electromagnetics of a current generator?

Thanks!!
Hydroelectric generators (the kind at big power stations run by water, such as at the Hover Dam) automatically generated AC electricity. For that matter, ANY uniformly revolving power source (wind, water, whatever) will cause a generator to produce AC electricity.

It's producing DC electricity that is difficult ... it is normally done they easy way by first generating AC, which is easy, and then using a full wave rectifier and associate circuit to convert it to DC.

meBigGuy
Gold Member
The current alternates in a sinusoidal manner because of the natural geometry involved in a rotating polarized magnetic field intersecting a wire. As said previously, creating DC is problematic. Producing currents requires changing magnetic fields. Simple motions result in sinusoidal currents.