I need to figure out how to adjust Hz coming from my outlet and, either raise or lower the frequency to the desired Hz. I need this for a coil I'm trying to power. Voltage doesn't matter as much though if it does in this case please let me know. I need to create variable frequency and change the Hz to between 0-3000hz. Again this is for a coil. Trial and error will come later. But I really need to make a PURE SIGN WAVE Frequency generator. Please help :'(

 

Easiest is to just buy a function generator (examples).

 

And then connect the Function-Generator to an appropriately sized Audio-Amplifier.
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Ditto. An off-the-shelf audio amplifier would be cheapest but won’t get you below 10-20Hz. If you could live with that, just use your smartphone as the signal generator and feed it to your audio amplifier.

A subwoofer amp might be the best choice to get to those low frequencies. They’re typically single channel and there’s no point to “wasting“ money on stereo.

 

"A Coil" is not just "A Coil".
Coils have Impedance because of Inductance, which changes with Frequency.
This is an extremely important factor to keep in mind.

If You would let us in on what You are trying to accomplish,
You might get some very valuable advice.
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"A Coil" is not just "A Coil".
Coils have Impedance because of Inductance, which changes with Frequency.
This is an extremely important factor to keep in mind.

If You would let us in on what You are trying to accomplish,
You might get some very valuable advice.
.
.
.

I'm trying to make a device out of parts I've collected from junk over the years. I want to understand every detail of the frequency generator and know how it works so I can master the craft. I have plenty of capacitors, resistors, mosfets, and hard drives and more that I've stored over the years. I would love to find a diagram of a property working frequency generator (pure sign wave frequency generator) so I can make one myself to understand through trial and error is the best way of learning for me so far. I need this device to power something like I motor not a speaker per say though it could be considered a speaker just with no magnetic parts. I want to just basically tweek the frequency to my liking anywhere from 30-3000hz minimum and maximum. It's hard to tell you what this is for but if it helps it's basically for a type of coil that I need to pump variable frequency thorough. Again at the range of 30-3000 Hz. If you can't help me it's okay I understand the struggles and sometimes it is easier to buy things. but Im someone who lives without money and I love to learn how everything works instead of becoming their consumer. It's hard to grasp and I don't want to lose you on this but I really wanna know how to make a frequency generator for that purpose. I'm sorry if I wasted your guy's time if you think YouTube and the Internet will be of better help I can go there as well. Regardless I appreciate your time you guys are extremely cool to me and I love the knowledge you all possess. Thank you for your time

 

So your aim is more of a learning experience, rather than an efficient way of doing it?
If not really needed, I would stay away from power outlet sources and look at LV sources for experimentation.
An example, but probably a simple way out when experience is what you are looking for, is a 3phase generator from an automotive scrap yard, The alternator without regulator for the DC produces 3ph AC
See

 

Building a variable-Frequency-Oscillator is not a trivial task.
It's not too difficult to build a FIXED-Frequency-Oscillator with a single Quad-Op-Amp,
and a handful of Resistors and Capacitors, ( that all must be very specific values ),
but variable Frequency is a bucket of worms.
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cheapest has to be a function generator kit from Aliexpress based on copies of the XR2206 or ICL8038, although for zero cost you can generate sine waves using a computer or smartphone. amplifier could be sourced from e-waste like an old TV or audio device, depending on requirements

 

A Kepco bipolar operational power amplifier is just the right thing for this job.

 

Actually, a variable frequency INVERTER circuit , which there are quite a few of them published, can be built for whatever power level you choose.
And certainly driving an amplifier from an oscillator circuit will provide an educational experience. BUT REALLY, you do need to also at least read about the theory related to what you are experimenting with. Randomly powering things without a clue as to understanding is a serious waste of time. And resources., such as those items collected over time.

 

To my knowledge, it's very difficult to convert a fixed frequency voltage to a variable frequency voltage without first converting the AC to DC then back to AC (read about cycloconverter for direct AC to AC conversion). A block diagram would go something like this:

Mains AC -> rectifier diode + smoothing capacitor (DC) -> voltage regulator (DC) -> variable frequency oscillator (DC) -> driver (AC) -> coil (AC)

This method doesn't use a transformer to step down mains voltage which means safety is a major concern for this circuit. That aside, generating a quasi-sinusoidal wave of variable frequency at the output coil is a sequence of somewhat basic sub-circuits.

But as other have said, the characteristics of the coil itself will influence how the waveform looks on the scope which may not look like a sine no matter what do you. This is an area of physics that is very much dependent on the materials and orientation of those materials in space. It's hard for anyone to say what you'll get from a bunch of components pulled from the scrap bin.

If possible, start with a step down transformer or better yet, a reliable DC voltage source. High voltage and inductive coils can be especially dangerous if you lack the knowledge and diagnostic equipment. All this said, I'm happy to go into more detail about how to build a prototype.

 

There's some information here which may help (assuming you want to experiment with mains outlet frequency conversion), not for the faint-hearted (mains is generally not experimenter-friendly)

https://sound-au.com/articles/frequency-conversion.htm

 

REally, for high power experimenting, get a big generator from"Northern Tool Company" and drive it with a variable speed engine. That will provide several thousand watts of power at an adjustable frequency.