Electrical isolation separates circuits so current cannot flow directly between them, while allowing signals or measurements to pass through appropriate means. It can be provided by components such as transformers, optocouplers, or isolated amplifiers.
In cyber security and hardware design, isolation helps protect people and equipment from hazardous voltages, limit unwanted electrical interference, and keep faults from spreading between parts of a system. In current sensing, an isolated sensor can measure a high-voltage or noisy power circuit without directly connecting its measurement electronics to that circuit. Isolation must be selected and rated for the system’s voltage and safety requirements; it does not mean that all electrical or signal coupling is impossible.