| 摘要 |
PURPOSE:To reduce the number of components used in the title circuit so as to simplify the constitution of the circuit by changing the rotating speed of the fan which is controlled by the circuit in accordance with the variation of the current outputted from the output terminal on the first capacitor side. CONSTITUTION:A main output DC voltage E01 is stabilized by controlling the turning on/off of a switching element 18. Although the voltage E01 drops due to the internal resistances of the first secondary winding 3b of a transformer 3, the first and second rectifiers 14 and 15, and the first choke coil 16 when the electric current flowing from an output terminal 21 increases, the output voltage of a transformer 4 rises and the sub-output DC voltage E02 on the second secondary winding 3c side rises and, as a result, the rotating speed of a fan 11 is reduced, because the voltage E01 is stabilized by means of a control section 18. Therefore, the rotating speed of the fan 11 can be changed in accordance with the variation of the output current by the use of a simple constitution. |
