pot trick (basic but usefull)

[richon]

very bored with paint --->





my question is....  would the RX resistor = 510K change the amount of signal that goes through the next stage (not showed)   I know this is true, as it  acts as a voltage divider...


but...

how big can Rx go till its harmfull 

(PS: the pot goes after the "input" JFET and before the "second" JFET stage)

the Goal is to limit the maximun of Gain to the next stage  and to control little amount of gain added.

PS2: would a voltage divider AFTER the pot work better?

[Taylor]

If Rx is 510k, then what you have is basically a 1MEG pot that can't ever be turned up past half. Yes, that will make the maximum output half of what it would be otherwise.

But changing the overall resistance of a voltage divider can in some cases make things not work the way they should. If the thing preceding that expects 500k impedance, and now it's seeing 1MEG, things may act differently.

If the original pot is 500k, and you want to limit the output of the voltage divider to half, use a 250k pot and a 270k Rx.

[richon]

thanks!


but, would it be strange to put a 470K+470K (voltage Divider) after the 500K pot to achieve the same result?