| 摘要 |
PURPOSE:To enable to adjust continuously the energizing ratio for a heating means having simple and low cost structure by a method wherein the alternate change-over timing of an electric power supply is made adjustable for the first heating means and the second heating means. CONSTITUTION:By pushing a selected oven key 13a of a key input means 13, a signal from the oven key 13a is inputted into a CPU 12b, a control pulse A is outputted from the CPU 12b. At the H level output from the CPU 12b, a variable capacitor 10a is charged, at the L level output from the CPU 12b, the output is discharged. An energizing ratio can be controlled by said charging and discharging time, when the voltage of a voltage waveform B exceeds the designated voltage, a relay 4a is driven. During an operating time of the relay 4a, an upper heater 2 is energized, during no operating time of the relay 4a, a lower heater 3 is energized. A relay circuit also a pulse width expanding or reducing circuit may be utilized instead of the variable capacitor 10a. |
