Change a potentiometer by a fixed resistor

[alambike]

Hello,

I would like to know how to change a potentiometer by a fixed reaistor.

For example, if the potentiometer is connected to the circuit in the respective way:

3 - signal from the circuit
2 - output
1 - ground

The fixed resistor would be:

One side in the place of the position 3, and the other will be the output??

And the position 1 to ground will be removed??

[vigilante397]

Depending on the circuit, yes.

[mth5044]

A pot could also be seen as two resistors. One resistor from pin 1 to 2 and another from 2 to 3. You'd have to measure the pot where you like it then replace with two resistors.

[GibsonGM]

Well worth checking out:  http://www.geofex.com/article_folders/potsecrets/potscret.htm

[alambike]

Thank you !

The circuit that I would like to change the potentiometer by a fixed resistor is the DAM meathead.



This is the case that I told.

If I think the potentiometer is two resistor, it will be two resistor in parallel. Some think like this :

[alambike]

Well,

I thought that I can use only one fixed resistor.

For example, in this case if I am using a 500K lin pot and I want to fix the value to 350 K ohm, I need to use R1 = 350K.

The follow Image shows what I am saying:

[ashcat_lt]

Neither of those work because you've got the whole thing shorted to ground, so I see silence.

If you want it all the way up, you don't need any resistors at all.  (Oh, maybe a pulldown from output to ground before the switch...)

If you want it down a bit, you need two resistors.  The easiest way is to just put one end of each where the wires to the pot go, connect the free ends together, and take the output from that junction.  If I understand what you want (just a little bit down, not mostly), then you need a 150K where the Volume 3 wire is, and a 350K where the Volume 1 wire is.  If you actually do want it mostly down, swap them.

[alambike]

So you mean that I do not need any ground connection ?

Vol3 + resistor 1
                             = output
Vol1 + resistor 2

The junction where both resistor end will be the output?

[alambike]

The image to illustrate what I told in the last reply:

Is it correct ?? 

[Quackzed]

thats it!!!  r1 would be the 150k and r2 the 350k. so if you look at it, there is 500k total resistance between vol3 and ground, just like a 500k pot. and if you measured the pot where you like it and there was 350k between the vol2(output) and ground, and 150k between vol3 and vol2(output), then this is the same as that only 'fixed'.
you got it!!! 

[ashcat_lt]

You got it.  Not exactly what I described, but it will work.

But...

So you mean that I do not need any ground connection ?

What I was looking at already had ground connected to Vol 1 via jumper.

[alambike]

You got it.  Not exactly what I described, but it will work.

But...

So you mean that I do not need any ground connection ?

What I was looking at already had ground connected to Vol 1 via jumper.

Connect vol3 and jumper to ground before R1, and after R1 is just output?

[ashcat_lt]

Connect vol3 and jumper to ground before R1, and after R1 is just output?

Ummm...

Already has Volume 1 connected to ground via jumper.  What I said was to put the resistors where the Vol3 and Vol1 wires are now, connect their free ends, and take output from that junction.  It's functionally the same as

except it fits into the scheme you already had without any further changes.  Your more recent image needs a whole new row on the vero.

[alambike]

What I said was to put the resistors where the Vol3 and Vol1 wires are now, connect their free ends, and take output from that junction

Your more recent image needs a whole new row on the vero.

Hello,

Thank you for help me!

I think this is the way that are you trying to tell me:



Another thing, to increase the out volume, this resistor value must be greater thank 500k or less than it ?

thank you

[vigilante397]

I think this is the way that are you trying to tell me:

Nope, that one won't work. You still have input going straight to ground without resistance.

[alambike]

Oh God ! hehe

I forgot about it ! Sorry...

I really can't understand what "ashcat_lt" is trying to tell me... 

Well, I will use the last scheme that I posted... That the "Quackzed" told: "You got it !"   

Thank you everybody for help me !