Direction of capacitors outercap

[Sagen]

Hi, can you tell me whats the right way to mount a capacitor. The capacitor has a inner and outer foil. The outerfoil is working as a shield to prevent noise entering the innerfoil.

So, I thinking then when using a cap in line with the signalchain as between output on PCB and RCA in a dac or preamp. I think signal from PCB entring the outerfoil on cap then to innercap and to RCA ( outerfoil works as a shield, not letting noise entering innerfoil ).

If turn around the outerfoil is picking up the noise an sending it down the signalpath?

Or am I wring here? The rule say outerfiol pointing the less impedance way to ground.

HELP!! ( :

 

[Galu]

The proper way to connect the outside foil is to the low impedance side of the circuit.

From an output to an input you would normally be going from low impedance to high impedance.

EDITED

 

[Mark Tillotson]

However most circuits are too low an impedance for it to matter much. Its only really an issue in the megaohm realm in valve circuitry, or very high impedance inputs. The higher the value of capacitor, the lower the noise voltages and the smaller the cap is physically the less it matters, as there is a capacitive divider in effect, one arm being the capacitance of the capacitor and the other the stray capacitance of the outer foil to the surroundings.

Or put another way it almost never matters with solid-state circuits.

And many circuits aren't affected - for instance with coupling capacitors the orientation won't affect noise pick up as at signal frequencies both sides of the capacitor see the same impedance, since the capacitor's impedance is very low (its a coupling cap).

 

[WntrMute2]

HERE is one way that worked for me in determining the outer foil. Did not experiment with trying them reversed.