# Dos and Don'ts - Every [[copper]] patch on the PCB must be electrically defined (and thus mostly grounded). If they are left floating, they can act as # Examples ## Heatsinks and Grounding Strategies - It is recommended to ground heat sinks, because if they are placed above high frequency ICs (>100MHz), parasitic currents can build within the heatsink making it act just as a huge antenna and thus creates electromagnetic radiation (EMI). This might cause the entire product to fail compliance tests or might cause problems in other sensitive circuits close by.