Editing Capacitive coupling (section)

==Parasitic capacitive coupling==

Capacitive coupling is often unintended, such as the capacitance between two wires or [[printed circuit board|PCB]] traces that are next to each other. One signal may capacitively couple with another and cause what appears to be [[noise (electronic)|noise]]. To reduce coupling, wires or traces are often separated as much as possible, or ground lines or [[ground plane]]s are run in between signals that might affect each other, so that the lines capacitively couple to ground rather than each other.  Prototypes of high-frequency (tens of megahertz) or high-[[gain (electronics)|gain]] analog circuits often use circuits that are built over a ground plane to control unwanted coupling. If a high-[[gain (electronics)|gain]] [[amplifier]]'s output capacitively couples to its input it may become an [[electronic oscillator]].