One of the main reasons that a circuit may need isolation is to protect it from damaging or dangerous currents and/or voltages. Isolation will also prevent dangerous voltages from passing to the operator during an electrical fault/failure or lightning surge. However, the flow of AC current transfer of power and signal will still be able to flow between two circuit system areas.
This article describes some various application examples that need isolation. Here are only a few general examples:
- Protecting human operators and low-voltage circuitry from high voltages.
- Improving noise immunity.
- Handling ground potential differences between communicating subsystems.