Evaluation of heat conductivity of thermosensitive ferrite as temperature dependence device

To realize the temperature control for implanted medical device called artificial anal sphincter utilizing shape memory alloy (SMA) board, a small transformer is made as a control device that consists of thermosensitive ferrite core. Thermosensitive transformer can transmit the electric power to the load heater at the temperature under Curie-point of the thermosensitive ferrite, and can intercept the power at the temperature over Curie-point. Then the power control depending on temperature can be realized. At the device applying only the temperature dependence of magnetic property, a machine trouble rarely happens, so the device can be used safely in a living body. The heat transmission property of the ferrite core was not quite suitable as a thermosensitive device. In this examination, the power loss at the magnetic core is regulated, and the heat transmission property is equivalently improved. Then a long time control of the SMA temperature is confirmed.