• Built with special insulation between primary and secondary, and tested, specified, and marked to withstand high voltage between windings, typically in the 1000 to 4000 volt range; designed with careful attention to capacitive coupling between the two windings
• Isolation transformers provide galvanic isolation and are used to protect against electric shock, to suppress electrical noise in sensitive devices, or to transfer power between two circuits which must not be connected together; suitably designed isolation transformers block interference caused by ground loops.