# Frequency adjustable 10 Watt sine wave generator

#### rtkale

Joined Jan 28, 2011
7
Hi!
I am looking for a 10 Watt sine wave generator.Amplitute will be 10 Volt and frequency range will become from 10 Hz to 100 Hz. I've googled it but there are so many sine wave generator types. I just need the answers of these questions.
1)how can I adjust frequency with a potantiometer?What will the pot change?
2)Since current is 1 A, I can not use mP, can I?
3)After I built up the oscillation circuit, can I amplify the signal in order to get 10 Watt?
4) What is your suggestions? (without microprocessors)
Any help will be greatly appreciated.

#### wayneh

Joined Sep 9, 2010
17,172
Are you TRYING to rule out microprocessors, because perhaps you are unfamiliar with them, or just because you think it's not needed? I think this project would be easier if you could use one.

How near to a sine wave do you need to be? Also, would it be OK to generate the sine wave somewhere else (eg. your computer) and then amplify it to the current and voltage you need? Even I could figure out a circuit to do that.

#### rtkale

Joined Jan 28, 2011
7
Thank you!
Sine wave will be used for rotating magnetic fields in order to model AC motors. I need it as an external device. I am going to put the circuit in a box. Without using a microprocessor, what is the flowchart of the whole process? Can you tell me what the first step shoul be? (I have checked some inverter circuits but I thınk I do not need a DC source)

#### studiot

Joined Nov 9, 2007
4,998
10 volts RMS times 1 amp RMS is indeed 10 watts RMS.

But 10volts is not the amplitude of the voltage,
Do you understand this basic electrical statement?

#### rtkale

Joined Jan 28, 2011
7
What I mean by 10 volts is peak value of the sine value. Actually, it is not so important. 1 V less or 1 V more is not critical in this application. What I need is block diagrams of the system, then I wıll start to build each block and finish the project. (for instance I am going to put a LCD which shows frequency value, this will be seperate block.) At first step, shuld I try to build the 10 Watt-10 Vpeak sine wave generator then I shuld add adjustable frequency circuit? or both these should be considered at the same time?

#### Kermit2

Joined Feb 5, 2010
4,162
At those freq. you could easily use a car audio power amp(12V), or a home audio power amp(120VAC).

All you would need would be an outout adj. low level audio function generator(100millivolt or so) to feed the amp.

CraNKkiTUPppp Dogg!

#### bertus

Joined Apr 5, 2008
22,089
Hello,

Do you need 1 output or multiple output on different phases?
In case of 1 output you will need 1 amplifier.
In case of more phases you will need more amplifiers.

For the amplifiers you could take a look at the LM1875.
These are 20 Watt power opamps.

Bertus

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#### rtkale

Joined Jan 28, 2011
7
Thank you for the answer. Your idea seems pretty helpful. But what do you mean by outout? is it a mistake or a term that I haven't hear

#### rtkale

Joined Jan 28, 2011
7
Hello,

Do you need 1 output or multiple output on different phases?
For the amplifiers you could take a look at the LM1875.
These are 20 Watt power opamps.

Bertus
I need one phase. (1 output). I will take a look at that IC. Thank you. If any ideas came to your minds, let me know..

#### bertus

Joined Apr 5, 2008
22,089
Hello,

The attached PDF contains a lot of information on making sinewave oscillators.

Bertus

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#### studiot

Joined Nov 9, 2007
4,998
You don't need to have a separate signal generator and amplifier.

Any reasonable power amp module can be wired into a low frequency power oscillator circuit.

So see what amp modules are available to yourself and look at Wein bridge oscillators.

#### rtkale

Joined Jan 28, 2011
7
Hello,

The attached PDF contains a lot of information on making sinewave oscillators.

Bertus

#### bertus

Joined Apr 5, 2008
22,089
Hello,

At the wienbridge oscilator as mentioned by studiot, the frequency adjustment can be done by a stereo (dual ganged) potentiometer.

Bertus

#### rtkale

Joined Jan 28, 2011
7
OK guys. Thank you so much for the fast help. I will use the information you gave to me and after some google research, I will be back and I will let you know what I found.
Regards...

#### studiot

Joined Nov 9, 2007
4,998
Here is a scan of such an oscillator circuit using an old power amp module.

If you want to pursue this I can make better quality available, send me a PM with an email address that can receive jpg files.

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