walters

I still don't get have PWM can make a (pf) Varactors into a (uf) varactors?

audioguru

Look at varactor diodes in Google.

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Uncle $crooge

audioguru

Of course not! The value is less when capacitors are in series.

Ridiculous.

Not possible.


Not available.

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Uncle $crooge

walters

sorry i ment

Varactors in "parallel " to increase the capacitances?

audioguru

You will be taught how PWM works when you learn something about electronics.

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Uncle $crooge

walters

PWM have duty cycle which changes the time constant of the Varactor capacitance

audioguru

No. PWM has a duty-cycle that changes the value of any capacitor.
Varactor diodes use a DC voltage or modulated DC voltage to change their tiny value, not PWM.
The tiny value of varactor diodes is useful only in radio circuits. I thought you are working with audio circuits using capacitor values that are thousands of times greater than varactor diodes.
So forget about varactor diodes for your circuit.

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Uncle $crooge

mstechca

You can use them in parallel.

microfarads??? :shock:
omg!
That means you will need at least 100,000 diodes in parallel that can produce a 10pF capacitance! By the time you inserted the 100,000th diode, you would probably have ran to us again :lol:

Thats it. and Walters, WHY would you need a varactor in Microfarads?

Why not increase the resistors that also affect the frequency you are dealing with so that you can lower the capacitance? Increasing resistors can help reduce power requirements and potentially extend battery life.

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-=: The best low-priced components to troubleshoot with are the speaker and the LED :=-

audioguru

Brilliant! Really.
I am glad to see that you have learned a lot and truly understand these things. :lol: :lol:

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Uncle $crooge

Nigel Goodwin

At the risk of taking his side, it doesn't help when the entire thread is pointless and confusing! :?

Still, as they say, "a little knowledge is a dangerous thing!".

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

mstechca

I knew that well before you even said BOO to me :lol: :wink:

Unless Walters has a definite goal in mind, I can see this thread entering more confusion.

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-=: The best low-priced components to troubleshoot with are the speaker and the LED :=-

Styx

Unless that is the goal

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Nothing is impossible.
Once a problem is realised, the rest is just details

mstechca

maybe you are right.

Maybe Walters wants to confuse everybody, including himself! :shock:

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-=: The best low-priced components to troubleshoot with are the speaker and the LED :=-

audioguru

Walters is confused because he wants to make electronic wah, wah sound effects mechanically in his 50 year old Leslie rotating speaker, by modulating its speed with exotic waveforms.
I think he also wants to make the Leslie speaker's sound electronically.
He also wants to fix his worn out 50 year old wah, wha pedal, but its special pot isn't available so he wants to convert an ordinary pot.

It would be confusing to a nooby and to an engineer to analyse the rotating phase shifts and Doppler FM effects of a Leslie speaker, then try to make the same sound and new ones with opamp variable allpass filter circuits.
If I had a guitar then I would also try to make the sound electronically, but I would probably use DSP instead of millions of opamps.

It boggles the mind, doesn't it? :lol:

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Uncle $crooge

Nigel Goodwin

Particularly when you can buy DSP based effects for very little money these days!.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk