Evolve power amplifiers 
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Super triode connection version 4

Because the circuit is interesting, I introduce the content here though I have not manufactured the amplifier which adopts this method yet.
It can be interpreted that the voltage of the plate is equal to the screen grid voltage because the screen grid controls the voltage of the plate as for the operation of the triode connection which connects the screen grid with the plate of the pentode shown in Figure 1.
The voltage amplification can be done in this part because the cathode control grid screen grid part forms one triode, and the plate be considered to do only the current amplification.
Then, I thought whether the same operation as this was able to be connected in other circuits.
[図1]  5極管の3極管接続
Figure 1:Triode connection of pentode


The output voltage is not fed back to the plate of V1 though the voltage amplification and the current amplification are allotted as for Figure 2 because the input signal voltage is amplified with V1 and it is output by the cathode follow of V2.

[図2]  カソードフォロワ出力
Figure 2:Cathode follow output

zu2.gif (3058 バイト)

[図3]  SRPP回路
Figure 3:SRPP circuit

zu3.gif (1980 バイト)


In SRPP of Figure 3.
RK should be a constant current for V1 to do only the voltage amplification, and contradiction is caused because RK should be a constant voltage to spread the output voltage to the plate of V1.

出力抵抗はおよそRo=rp/Rp gmとなります。

Then, I began to think about the super triode connection version 4 shown in Figure 4.
The operation of this circuit controls V3 by V2, and equates the output voltage with the voltage of the plate of V1.
The output resistance becomes about Ro=rp/Rp gm.
The voltage amplification characteristic depends on the triode characteristic of V1.

[図4]  超3極管接続バージョン4
Figure 4:Super triode connection version 4

[図5]  超3極管接続バージョン4の応用
Figure 5:Application of super triode connection version 4
drive amplifier

zu5.gif (2070 バイト)

stabilization power supply

zu6.gif (2322 バイト)


The circuit which replaces V1 and V2 with one pentode is simple as shown in Figure 5 and practicable.
There is a voltage gain. It is low output resistance to surpass SRPP and the cathode follow. The distortion is a little. Therefore, this can be used as a simple, efficient drive amplifier.
Moreover, this can be applied as a stabilization power supply by using the constant voltage characteristic of the output.

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Copyright © 1997 Shinichi Kamijo. All rights reserved.
最終更新日: 2000/04/23 11:33:24 +0900