A control circuit (9) operates a power switch (11) for the cooking plate (13) via a relay (10). The power switch (11) is connected in series with a power setting switch (12) and is bridged by a high-ohmic resistance (14) detecting the switch position of the power switch. When the latter and the power setting switch are both in the open position a signal is supplied to the control circuit (9) to allow it to be switched back from automatic operation to manual operation. Pref. the signal line from the high-ohmic resistance (14) to the control circuit includes a resistance (18) and a diode (21) for level matching.
