Separate control. The reason why the four rice cookers only have temperature control switches is because the electric frying pan has three switches to control the three heating pipes respectively, which constitutes the three-stage temperature adjustment of the electric frying pan, namely, the low temperature, the medium temperature and the high temperature. The fourth switch is connected in series with the temperature controller and the heating tube to form a heat preservation circuit, so that the electric frying pan has a heat preservation function.