Amplifier for exerting negative feedback on electronic tube screen grid

A technology of negative feedback and curtain grid, applied in the direction of negative feedback circuit layout, etc., can solve problems such as linearity deterioration and output power reduction, and achieve the effect of improving linearity

Inactive Publication Date: 2008-09-24
张东静
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The amount of negative feedback applied to the curtain grid determines the characteristics of the components. The above-mentioned super-linear connection method controls the amount of negative feedback of the screen grid, and improves the linearity of the pentode at a small cost: The linear tap is at the position of the primary coil of the output transformer, the closer to the side of the screen electrode, the greater the amount of negative feedback applied to the screen grid, the more severely the output power is reduced, and the closer the triode connection is to the side of the power supply voltage, The smaller the amount of feedback, the higher the power, but the linearity becomes worse

Method used

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  • Amplifier for exerting negative feedback on electronic tube screen grid
  • Amplifier for exerting negative feedback on electronic tube screen grid
  • Amplifier for exerting negative feedback on electronic tube screen grid

Examples

Experimental program
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Effect test

Embodiment 1

[0024] figure 1 The circuit diagram of the first embodiment in the present invention, image 3 yes figure 1 power circuit diagram. The driving signal voltage required by the directly heated triode grid is very high. In order to obtain a sufficiently high driving signal voltage, a pentode is often used as a voltage amplification stage.

[0025] In order to improve the amplification linearity of the voltage amplifying pentode V1, this scheme adds negative feedback to the curtain grid G2 of the voltage amplifying pentode V1 through the coupling capacitor C2 to form a voltage amplification stage, and uses the resistor R3 to provide a DC voltage for the curtain grid G2. It not only improves the linearity of the voltage amplification pentode V1, conforms to the rated working voltage of the pentode curtain grid and the screen electrode, but also has a higher output signal voltage to push the grid of the direct heating triode V2. In the figure, the DC power supply of the voltage ...

Embodiment 2

[0030] figure 2 is the circuit diagram of the second embodiment of the present invention, the power amplifier stage and figure 1 Similarly, the gate fixed bias resistor of pentode V1 is connected to figure 1 Same as its power circuit with the figure 1 The power circuit is the same. What is provided is to use the Zener diode to reduce the DC voltage of the screen electrode signal, and the negative feedback amount is determined by the voltage dividing ratio of the voltage dividing resistor. This method is a circuit formed after further improvement and optimization of the circuit in Example 1, and is replaced by fixed resistors R4, R10, and R11 with corresponding resistance values figure 1 The potentiometer W3 and resistor R4 in the circuit are used as the screen pole load, and the zener diodes DW1 and DW2 are used instead of the coupling capacitor C2 to apply negative feedback and provide DC voltage to the curtain grid G2 of the voltage amplification pentode V1. The part...

Embodiment 3

[0033] Figure 4 It is the circuit diagram of the third embodiment of the present invention. Specifically, a negative feedback servo circuit is used to provide a negative feedback signal for the curtain grid of the power amplifier pentode. This negative feedback servo circuit also provides a curtain grid for the power amplifier pentode. The gate provides a constant current source of DC voltage. Figure 5 yes Figure 4 The power supply circuit diagram in the figure, Q9, R23, and C10 in the figure form an active filter circuit to provide DC power for the amplifier. Such as Figure 4 , Figure 5 As shown, a negative feedback servo circuit is used to provide a negative feedback signal for the curtain grid of the power amplifier pentode. The curtain grid of the five-pole power amplifier tube V2 is connected to the servo circuit composed of Q1 and Q3, and the constant current source of Q1 is connected to the curtain grid of V2, which is composed of Q3, R13, D5, and D6. The active...

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PUM

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Abstract

The invention discloses an amplifier which applies a negative feedback on the plate grid of an electronic tube; after a signal is amplified by a quintode or a beam power tetrode, a part is taken out and then a negative feedback signal is applied to the plate grid of the quintode; the quintode of the amplifier provides a negative feedback AC signal for the plate grid by a coupling capacitance / a Zener diode / a negative feedback servo circuit / a negative feedback winding / a connecting plate grid, a DC voltage for the plate grid is provided by a resistance / the Zener diode / the negative feedback servo circuit / a choke / the negative feedback winding / a connecting plate grid. The scheme can also be suitable for the beam power tetrode. The amplifier of the invention can be used for providing an AC negative feedback signal with a fixed amount for the plate grid, improving the linearity of the quintode or the beam power tetrode and being capable of adjusting the negative feedback amount applied on the plate grid no matter applying the quintode at a voltage amplifying stage or a power amplifying stage; the plate grid and an anode can respectively work at the rated operational voltages of each own when the DC voltage of the plate grid is lower than the anode.

Description

1. Technical field [0001] The invention relates to an audio frequency tube amplifier, in particular to an amplifier with negative feedback applied to the screen grid of the tube. 2. Background technology [0002] Connect the pentode screen grid and the screen electrode with the rated working voltage of the screen grid lower than the rated working voltage of the screen electrode to act as a triode to improve linearity. No matter it is applied in the voltage amplification stage or in the power amplifier stage, it takes a lot of effort. Big price. In the voltage amplification stage, the triode connection reduces the amplification capability of the pentode to the level of the triode; in the power amplifier stage, the triode connection reduces the output power by more than double. [0003] The super-linear connection method applies a certain amount of negative feedback to the curtain grid, which improves the linearity of the pentode without reducing the output power much. Althou...

Claims

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Application Information

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IPC IPC(8): H03F1/36
Inventor 张东静
Owner 张东静
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