Electronic circuit question

[HaLDoL]

I'm new to electronic circuits and so but I did some mods on my nf7 recently and most of them are the one-leg-of-pot-to-chip-other-leg-to-ground kind of mods.
Now when I measure the resistance before connecting to ground, I always get a different value than when the wire is connected to ground.
Usually when it is connected to the ground, the resistance is much lower.

Can someone explain this from an electric point of view? How come that the ground is lowering the resistance?

[Ragnarok]

that's because when connect a resistance from the feedback to the ground, it is in parallel with other resistances, and reduces the overall resistance seen from those two terminals..

[chilly1]

Basic electricity....


Resistors
in parrellel 1/R.t = 1/Ra+1/Rb+1/Rc + ...
in series Rt = Ra+Rb+Rc + ...
Capacators
in parrellel Ct = Ca+Cb+Cc + ...
in series 1/Ct = 1/Ca+1/Cb+1/Cc + ...

E= I x R
P= I x E

E in volts

I in amps

R in ohms

P in Watts

[Ragnarok]

well a more useful equation for 2 resistor in parallel or 2 cap in series is

R1*R2/(R1+R2), C1*C2/(C1+C2)

note this does not apply to more than 2 elements

[HaLDoL]

Thanks for the explanation, I knew it had to be something like that ;)
So if a vmod guide tells you to put the resistance of the pot to 5k, this means 5k measured when the pot isn't connected?

[enzoR]

yes