| 摘要 |
<p>A toaster has electrical parts which are energized from a mains voltage. The bread is conveyed to a toasting chamber (4) by means of a lift (6) and a handle (12). In the end position of the handl (12) a main switch (SW5) is turned on, as a result of which the electrical parts can be powered from the mains voltage. The heating elements receive mains voltage via triacs controlled by a microcontroller. After completion of the toasting cycle the microcontroller turns off the heating elements, which precludes burning of the bread, even if the main switch remains in its on-position as a result of a mechanical defect. Subsequently, the microcontroller checks the presence of the mains voltage. In that case a signalling device is activated to warn the user that the mains voltage supply to the toaster has not yet been turned off.</p> |
