| 摘要 |
PROBLEM TO BE SOLVED: To improve the attenuation of an amplification factor in high pass audible frequencies by decreasing a voltage and connecting this voltage from a middle point obtained by dividing a plate resistance into two through a fixed voltage Zener diode with a screen grid. SOLUTION: In a voltage amplification resistance connecting circuit constituted of a multielectrode electronic tube, a voltage is decreased and connected from a middle point obtained by dividing a plate into two through a fixed voltage Zener diode with a screen grid so that an inner resistance can be decreased without deteriorating the life of a multielectrode electronic tube. In this circuit, the fixed voltage Zener diode voltage is selected so as to be a proper voltage value so that the screen grid voltage can be set so as to be a voltage within the maximum specification. In this circuit, the plate resistance intermediate point voltage is set so as to be 290 V, and the screen grid voltage is set so as to be 86 V when a voltage amplification power supply voltage is 363 V. In this case, the screen grid voltage of a voltage amplification electronic tube WE 310A can be operated with a sufficient margin against the maximum specific voltage 180 V.
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