Patent ID: 8905634

Claim:
A temperature detection apparatus configured to detect temperature of a heating element to which a high voltage is applied, said apparatus comprising: a transformer; a thermostat attached directly to an electrically conductive site of said heating element and having contacts that become short-circuited or come into an open-circuit condition depending on whether or not the temperature of said heating element is equal to or higher than a predetermined value, whose contacts are connected to a secondary coil in said transformer; a DC voltage source and a transistor configured to supply required AC power to a primary coil in said transformer; a current detection resistor configured to detect a current flowing through the primary coil in said transformer; and a comparison circuit detecting a voltage generated across said current detection resistor when a current flows through said current detection resistor, said comparison circuit outputting an alarm signal when the current flowing through the primary coil in said transformer exceeds a preset threshold current.