Sine Wave Generator with a 555 Timer

In this video, I demonstrate a sine wave generator circuit built with a 555 timer chip. I put the chip in astable mode to produce a square wave and then place an LC resonant circuit at the output to convert it to a sine wave.

[abdelbaki]

Nice. This technic is called filtering. To achieve a better result, you must ensure that the resonant frequency of the LC network matches the timer frequency. As 555 timer oscillation is most often based on an RC network, this frequency can be tuned using a potentiometer. At the resonant frequency, the peak to peak voltage is maximum as the capacitive and inductive reactances are opposite. The sum is therefore zero.

[Azninjazn]

im getting more of a triangle wave instead of a sine wave

[Ezio-Auditore]

That sine wave has a little bit of saw shape, there is a way to reduce that and make it more sine like? Great video

[FugitiveZ]

@ElectronicsLearning - I agree with amilom007. Although you changed the square-wave to look a bit more like a sine-wave, it's not pure enough and looks more like triangle-wave. It would cool if you could the math and make the changes so it's more sine-wave(ish). I'm clueless so it's all up to you!! - But I'd like to see if it can be done.

As for ALEFILE's question about the inductor, I too would like to know how to build one, winding my own coil, rather than buying off the shelf - but again I'm clueless as to how many turns of what awg wire to create the required 470 Henrys. --- B!LL!

[atomictraveller]

looking at your circuit and writeup, you describe swapping the R value to change frequency. i know if you throw a pot in there the pulse width will also change, and that by selecting resistor values you can find a range that works alright for audio (just fun like a toy raygun not a eurorack or anything critical). as i understand it the inductor works like a bandpass (i know audio dsp well) - my question is if i build this with a potentiometer, how much pitch range before the bandpass drops the gain? or would the inductor and resistance track the cutoff together to maintain gain over several octaves?
thanks for documenting this method! i like being aware of things that "work well enough"!

[ALEFILES]

Many thanks for this nice circuit! In your web site, you use an 470μH inductor ("L"). How did you calculate the number of turns and the diameter of the coil? Thanks for your wonderful videos!!!

[dalenassar]

Can you adjust the frequency only and get any decent sine frequency oscillations without changing the LC filter. Will the amplitude be greatly altered?
THANKS FOR THE VIDEO!!

[rel]

This is triangular wave with a bit curvy shape, but not sine wave.

[ANTALIFE]

You are using the LC circuit as a low-pass filter, pretty sure resonance does not have anything to do with it

[digitalhands]

It's just a low pass filter. you'll get nothing but a dc signal in higher frequencies.

[JCHaywire]

With all due respect, how is that not a triangle wave? Isn't the definition of a triangle wave confirmed by your oscilloscope?

[Animinetor]

Can i amplify with a mosfet and use voltage multiplier

[abrahamghannam]

Thanks I have no idea what you’re talking about

[chrishill]

That is not a good approximation of a sine wave. You are filtering the fundamental plus some harmonics to give an approximate triangle waveform. You would get a better approximation of a sine wave if you configured the LC low pass filter to have a lower cut off frequency. You could see this better if your scope has an fft function. Also, I wouldn’t describe this as a resonator, more an astable multivibrator with a LC low pass filter on the output.

[aduedc]

What is the phase noise of your circuit?

[saddamalradai]

Is it OK to use it as an oscillator in power inverter, as sine wave with adding buffer in lc circuit, if that so, I will start to design it. thanks for the video

[sripranav]

Can we use this output to our home hold applainces

[jacobjacobs]

can you share to us how you made your LC CIRCUIT?

[sagar-cbiu]

What is the frequency range? Pls reply

[onthelinuxway]

the signal goes from -5v to +5v ? or it goes from 0v to +5v ??