“Isolation” in circuits and systems means that there is no galvanic (ohmic) path between an input and an output. Most engineers are familiar with isolation of AC power lines using a transformer, which is standard practice in many line-powered designs and AC adapters/chargers.

But isolation is often also needed for signals and subcircuits, so a signal’s information can flow to another part of the system, but without a physical path. There are many reasons for need, including system and user protection; signal integrity; non-grounded and floating measurements, and ground separation.

This Fundamentals course will briefly look at power isolation (often required in conjunction with signal isolation) and then focus on signal isolation techniques. It will look why it is needed, where it is needed, the relative attributes of techniques for implementing it, and other considerations.