| 摘要 |
PURPOSE:To improve the efficiency of a captioned device by adopting a construction to convert the detected amount of blast by a blower motor into a guantitative signal and thereby indicate the amount of blast for prolonging the time of automatic operation as possible. CONSTITUTION:When a selection mode is turned into ''AUTO'' and a switch 2 is closed, the amount of blast is automatically controlled, and the output of a differential amplifier 6a is increased and decreased in accordance with the change of the relation between the supplied voltage to the blower motor 3 and the lowering of voltage of a resister 4. Since this change of increase and decrease is amplified by a transistor 6d to change the collector current flowing in a resistance 6c, the blast amount of the blower motor 3 can be obtained by the potential difference given by the collector current of the transistor 6d between both ends of the resistance 6c, and this is taken out in an indicator 7 for indicating the amount of blast. This construction permits to see the amount of blast by eyes, and fix the mode at ''AUTO'' to maintain the automatic operation for a long time and improve the efficiency. |
