RC Filter component placement
Personally, I prefer to skip the "which side is in" controversy &amp; simply use a "T" or "pi" filter network for RF signals.







simulate this circuit &ndash; Schematic created using CircuitLab

Firstly, this avoids having to debate which side of the resistor to attach the capacitor to, and secondly it allows me to sneak in some "impedance matching wizardry" along with the filter, if it happens to be needed.