Friend of mine argued with me that you can't get a sinewave output from a 555 timer. Simulation below shows you can. Cost him a few pints! :wink:

LC oscillation frequency will be more stable than RC mode.

Attached Images

555_sine.gif (33.0 KB, 891 views)

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i'm somewhat dumbfounded at this diagram. The output of a 555 cant be sinewave, unless you have something to smooth off those corners.

:? please explain

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Note that I picked my words carefully, and not said, you get a sine wave from the output of the 555 :wink: there's a difference!

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Owned

I agree it is possible to get a sine wave.

I wonder what is used in high quality inverters.

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i think inverters use bridge circuits (half bridge and full bridge) and they produce a pure sine wave.

by the way TheOne which software is this that you use for simulation

 

Proteus Pro. You can download a lite version free

http://www.labcenter.co.uk/

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\"You can\'t make a circuit fool-proof, cause fools are so ingenious!\"

 

It is fairly simple. We have a 10kHz pulse input. The L and the two C's forms a resonator (pi-filter) at the required frequency, giving 180 deg phase shift (higher order harmonics attenuated after passing through the resonator), and together with another inversion going through the 555 gives a total of 360 degrees. This in-phase feedback together with > 1 (~4) gain through the 555 satisfies the condition for sustained oscillation.

Graph of the Fourier (spectrum) analysis show the harmonic content at the input of the resonator and how only the fundamental remains at the output.

Attached Images

square_to_sine_112.gif (34.8 KB, 748 views)

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\"You can\'t make a circuit fool-proof, cause fools are so ingenious!\"

 

And just to prove that the 555 acts only as a invertor like I previously explained, I replaced the 555 with a logic invertor. The result is the same, oscillation at 10kHz

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square_to_sine1.gif (28.0 KB, 720 views)

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\"You can\'t make a circuit fool-proof, cause fools are so ingenious!\"

 

In fact it does not matter what we use for the invertor, as long as it has enough gain to overcome the losses around the circuit, you will have oscillations. Here on the left, a common emitter amplifier with gain >1 completes the loop, and once again oscillations at 10kHz. Even a JFET will do nicely as shown on the right.

Attached Images

square_to_sine2.gif (80.5 KB, 694 views)

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\"You can\'t make a circuit fool-proof, cause fools are so ingenious!\"

 

And lastly, Zach one specially for you. Here we even kicked your IRF510 into oscillation. The pot on the gate is set to be near the gate threshold voltage (~2.5 - 3V)

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510_0sc1.gif (30.1 KB, 665 views)

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\"You can\'t make a circuit fool-proof, cause fools are so ingenious!\"

 

Could you attach the files of those schematics, I'm trying to learn how to use Proteus Pro demo and it would make things seasier for me to browse through the circuit and check how did u configure the values and stuff.

Thanks

 

I don't have all of them anymore as I modify old ones into new circuits. If you PM me I could email you the ones I still have. Also I am not sure that all will run on the demo version cause of the models.

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\"You can\'t make a circuit fool-proof, cause fools are so ingenious!\"

 

Here's another inverter you can use.

0x34

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741-sineosc.jpg (104.1 KB, 564 views)

 

effectively all this is doing is harmonic-scrubbing of the actual outout of the 555 which is a squarewave

still good, could never scub a sinewave that well

 

thanks for the methods....