| 摘要 |
PURPOSE:To improve the power efficiency for the load impedance by performing automatically control so that power consumption of a collecter-grounded transistor amplifying circuit may be an apporximately minimum value according to change of the value of the load impedance. CONSTITUTION:The AC signal inputted to input terminal 72 from, for example, a level-stabilized oscillator is supplied to load 21 after amplified by transistor TR33. The AC signal current supplied to load 21 is detected by a rectifier circuit dependent upon diodes 58 and 59 through minute resistance 41 and transformer 42 to control TR63. TR63 is connected in series to TR33 for amplification in DC and performs control so that the DC current of TR33 for amplification may be an optimum and minimum current for the impedance of load 21 according to impedance fluctuation of load 21. |
