im getting a noisy output in falstad

[Electroplater]

Ok, so something funny happened to me in falstad, and I got an audio output of an oscillator with a resistor there,
and it was just noise!??

I changed it to 1 ohm and then the 1k harmonic appeared in the noise.

This would make me think resistors are noise generators and u cant use them in synths without being a noise generator, but thats got to be false otherwise nothing else would have worked if that was true.

So im thinking, its not true, that resistors generate noise to a large degree. (I couldnt even hear the wave at all at 10 ohms) So its got to be a falstad mishap of mine, so can anyone help me here with whats going on?

 

[Electroplater]

Just an update, I tried it with square wave, and then it worked.

But it was because it was a sine wave that I got nothing but noise.

Is this a falstad error? Or is there some truth to it, and u can make a noise generator with a resistor?

 

[danadak]

Post the simulation so forum can run it.


Regards, Dana,

 

[Electroplater]

https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l5YCsA2ATIq1mNZAHGAJxi4DMpCJIaIGiktApgLRhgBQATiKnnuAHZkPPjwAsDBmHjsAbiP5tUCwcKnh4tKNpiJ2AdxWoJRgcsgHTysaWWozUSzbsPn4KhcNulKnxdRsIN5UiGJi7ubgIHiaHEA

here is the code. Put the simulation speed to top, wait for the audio buffer to fill and click play audio.

But strangely now im getting 0 OUTPUT! silence! I dont know whats going on, can u please save me.

 

[Electroplater]

PLEASE CAN SOMEONE HELP ME!!! Im stuck with this.

I spose I can get on with the rest of my circuit, but I have to guess that this is just ******** and u can put high resistances in a synth and the thermal noise is not much at all, and this is all diverting me away from it.

 

[danadak]

https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l5YCsA2ATIq1mNZAHGAJxi4DMpCJIqhIGikdApgLRhgBQATiACympwyRv0GpUvKOHgcAbtTx5wVVIuoB2QYwhh4dKYxiIOAdz4DlYtey0dU7c4Jt1ek59pB49nM6KEiLd1NHagkQ1E0oDgBzEFIcDUF4pMhJQ2DVJQikhOyo3ws85MSogHs+aileSEIlDBgIRkFJUg4gA

This seemed to work. I think your issue was because you did not have a ground reference.


Regards, Dana.

 

[Electroplater]

that just pisses me off, so i have short away from ground pointlessly just to get the audio to work.

But thankyou.

 

[Nigel Goodwin]

that just pisses me off, so i have short away from ground pointlessly just to get the audio to work.

If you don't conect the ground wire from your scope (even an imaginary one), how do you expect it to work?.

 

[Electroplater]

if i dont connect my ground to my battery circuit, then it doesnt operate does it.

the ground wire of the scope, doesnt even need to be one, I spose it could be one, but it could just be any wire to go into the system.

 

[Nigel Goodwin]

if i dont connect my ground to my battery circuit, then it doesnt operate does it.

the ground wire of the scope, doesnt even need to be one, I spose it could be one, but it could just be any wire to go into the system.

A scope (like a meter) can't work without a reference to measure from - this is normally ground.

If you don't like the word 'ground' then you could use 'earth' if you wish, or perhaps more usefully 'chassis'? - it doesn't matter what you call it, a reference point has to be there.

 

[Electroplater]

theres no need for it in this falstad sim tho, definitely.
its in there for very little reason.

 

[danadak]

theres no need for it in this falstad sim tho, definitely.

its in there for very little reason.

Thats not quite right. Voltage is measured between 2 points, it is an electrostatic physical
measurement.

Voltage - Wikipedia

en.wikipedia.org

Regards, Dana.

 

[Electroplater]

its just a fricken audio buffer to fill, wheres the harddisk floating in the air in real life for that part of the falstad sim.

 

[Nigel Goodwin]

theres no need for it in this falstad sim tho, definitely.
its in there for very little reason.

It's in there to make it work - and it didn't work until you added it, surely that tells you something?.

 

[Electroplater]

Yes, tells me that its stupid.

 

[rjenkinsgb]

Yes, tells me that its stupid.

You are assuming that measurements are always to 0V.

That may be the commonest, but often you need to measure between two different non-grounded points in a circuit.

eg. Measuring across a amplifier load resistor or series resistor with neither side grounded. You need two leads, as with a multimeter.

 

[Lightium]

I think your better off simulating with ltspice. You can use the .wave command and an audio player of your choosing.

 

[Electroplater]

isnt it better to be able to play out of the program itself instead of having to quit out and launch things over and over.

 

[Lightium]

Ah, don't you have a multitasking op?

 

[Electroplater]

what is one of those things? what does op stand for? optimization - i doubt it tho, thats what i call it.