| 摘要 |
<p>PURPOSE:To attain a uniform baking characteristic independently of an initial temperature by providing newly a means which varies automatically a preheating time in accordance with the initial temperature of the inside of an oven. CONSTITUTION:When a prescribed time elapses after a switch SW is turned on, the terminal voltage of a capacitor 1 rises, and a Zener diode ZD1 is made conductive to make a transistor TRQ1 conductive. Then, a main timer MT starts the operation, and baking of foods in the oven is started, and baking is terminated after the time set by the main timer MT. Then, a relay RY is turned off to break the power supply to the TRQ1, and the Zener diode ZD1 is cut off, and the electric charge of the capacitor C1 is discharged gradually through a resistance R2 for discharge. If the start switch Sw is turned on again in this state by the operator, the TRQ1 is made conductive in a timer shorter than said state because of the existence of a residual electric charge of the capacitor C1, and therefore, the preheating time is shortened.</p> |
