AUTOMATIC POWER-OFF PROTECTION APPARATUS

摘要

An automatic power-off protection apparatus includes an alternating current (AC) input; an AC output connected to the AC input via power wires that comprises a naught wire and a live wire; a switching unit for enabling and disabling a connection between the AC input and the AC output; a first pair of coupling coils for producing a first induced AC voltage; a second pair of coupling coil for a second induced AC voltage; an operational amplifier for amplifying a voltage difference between induced voltages across the first secondary coil and the second primary coil; a first and second comparator for comparing the amplified voltage difference with a first reference voltage and a second reference voltage respectively. The automatic power-off protection apparatus cuts off the path between the AC input and the AC output when detecting current leaks.