No, the most basic rice cookers are very simple. They use a spring-actuated switch and a magnet paired with an alloy button in contact with the bottom of the cooking bowl that has a Curie temperature just slightly above the boiling point of water. When the rice has absorbed all the water the temperature can finally begin to exceed boiling and the button heats up with it, causing the magnet to lose attraction to it. When the magnet is no longer able to overpower the spring, the switch opens and cooking is shut off (usually into a low power keep-warm setting) [1].