Instrumentation Reference Book, 4th Edition

45.3. Circuits, Layout, and Grounding

Designing for good EMC starts from the principle of controlling the flow of interference into and out of the equipment. You must assume that interference will occur to and will be generated by any product which includes active electronic devices. To improve the electromagnetic compatibility of the product you place barriers and route currents such that incoming interference is diverted or absorbed before it enters the circuit, and outgoing interference is diverted or absorbed before it leaves the circuit.

You can conceive the EMC control measures as applying at three levels, primary, secondary, and tertiary, as shown in Figure 45.20 . Control at the primary level involves circuit design measures such as ...