| 摘要 |
PURPOSE:To control a high frequency output and to imporve the utilization efficiency of a power source by varying a DC source voltage impressed on a collector of the final step transistor. CONSTITUTION:A high-frequency signal generated by an oscillating circuit 1 is amplified by a driver transistor 2 and inputted to a high-frequency transistor power amplifying circuit 3. The driver output is a signal having a fixed amplitude and the value of said amplitude is larger than that where a collector current of the final step transistor of a power circuit is saturated, the power circuit 3 amplifies by C grade the input signal, and the output is applied to a plasma load 5 through a power measuring part 4. The DC source voltage is applied to a collector of the final step transistor of the circuit 3 through a voltage variable part 7. A voltage signal proportional to the output of a power transistor 3 is fed back to the part 7 from the part 4 through a voltage comparator 8. Thereby, the output of the power transistor is stabilized. |
