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Amplifier Circuits-Vacuum Tube

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805 Vacuum tube transformer push power amplifier circuit

Published:2011-5-13 4:49:00 Author:May | Keyword: power amplifier, Vacuum tube, transformer push

805 Vacuum tube transformer push power amplifier circuit
The 805’s features of high essential resistance leads to that the inductance value output transformer needed is larger. In addition, the other problem caused by it is that output impedance is too high and damping coefficient is decreased. It is a common 805 circuit without transformer secondary sampling negative feedback. Its damping coefficient is 10K/tube essential resistance (10K)=1 and is lower when output transformer’s primary impedance is 10K. And it is lacking proper controlling force to speaker. Low frequency has lager quantity but low quality. Also, the damping coefficient of 300B vacuum tube with 700Ω essential resistance is 3.5K/700Ω=5 and it has effective controlling force to speaker when it adopts 3.5K output transformer. So, the 805 class essential resistance tube should add negative feedback which the sampling point is output transformer’s primary, and the familiar is negative feedback loop. It can make the essential resistance of 805 decreasing some by suitable decreasing the working voltage (suitable decrease output power) and improving 805 working current (with litter influence the designing and making of output transformer). But it is not the main method.   (View)

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Space-saving HVArc Guard Capacitor goes for Passive Buffering Circuit

Published:2011-9-3 10:25:00 Author:Zoey | Keyword: Space-saving, HVArc Guard Capacitor, Passive Buffering


Many passive accessories can be used to make passive buffering circuits, and to absorb energy of reactance on switched circuits. Buffering circuits can pinchoff pulse noise, reduce power losses while cutting off circuits and reduce peak voltage on switches. New HVArc Guard high pressure MLCC capacitor gathers the attributes such as high breakdown, low impedance, and wide work frequency scale together. What’s more, its size is as small as 0805. HVArc Guard have excellent surge restrain capability. Here are the statistics for surge test on HVArc Guard capacitor. C0G(N0P)HVArc Guard X7R HVArc Guard   1.2μs×50μs 1650V 500V   10μs×700μs 1800V 1200V   10μs×160μs >1500V 1200V Following picture is an example for buffering circuit of totem pole MOSFET circuit.   (View)

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Norton_triangle_wave_generator

Published:2009-7-17 4:30:00 Author:Jessie

Norton_triangle_wave_generator
This circuit uses one section of an LM3900 to form a triangle-wave generator. Notice that the circuit also produces a square-wave output at the same frequency. National Semiconductor Linear Applications Handbook, 1991, p 233   (View)

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The amplifer circuit diagram formed by LM118 and used in device

Published:2011-7-16 2:49:00 Author:leo | Keyword: Instrument amplifer

The amplifer circuit diagram formed by LM118 and used in device
Picture 1 is an instrument amplifier. It is made up of LM118 and others. In this circuit, VT1 and VT2 can form surface input circuit. They can form constant flow source which can supply steady current for differential amplifier A1;VD1 can supply base voltage(1.2V) with zero degree temperature factor to constant flow source. In order to make the input circuit have a good linearity working state, The output current of VT3 and VT4 should be double ofthe current passing through it when being added differential voltage.If needing smaller input current, all resistances should be increased by 100 times and replace LM118 with LM318.   (View)

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A differential value detecting circuit made by LTC1043

Published:2011-7-16 2:50:00 Author:leo | Keyword: Detecting circuit, differential value

A differential value detecting circuit made by LTC1043
As the picture a and b show, this is a differential value detecting circuit made by LTC1043, in which the differential terminal is changed into single terminal output terminal. Picture20 (a) shows the basic detecting amplifier with speeding up capacitor mode. The sample C1 is connected to differential input signal terminal and uses differential input voltage Ui to charge. And LTC1043 is used to handoff and connect C1 to C2 while the electric charge of C1 is transferred to Q. Due to the repeating frequency of hundreds to some dozens of thousands, voltage of the differential input signals changes to signal input voltage of A1. The repeating frequency is decided by LTC1043 and capacity of C3(EXT capacitor ).   (View)

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ULN2204,LN2204A,LN2204A 21 single chip audio integrated circuit

Published:2011-7-13 20:00:00 Author:leo | Keyword: Single chip, Audio, Integrated circuit

ULN2204,LN2204A,LN2204A 21 single chip audio integrated circuit
ULN204, ULN2204A and ULN2204A—21 are a kind of single chip audio integrated circuit used in pocket-sized radio and other kinds of radios. 1.ULN2204 integrated chip inner circuit diagram and pin functions:ULN2204 AM part contains AGC, MIX, LO, ZF and detecting circuit. The AM part does not include AGC and MIX circuit but only ZF and frequency discrimination circuit. Its pin functions are shown in the picture. 2.ULN2204 main parameters:The integrated circuit ULN2204 has a operating power supply voltage coverage of 3 V to 12 V with the classic voltage of 4.5 V.(1)When Ta is 25℃ and Vcc is 13V, the power consumption P(D) is 600 mW and current I(REY) is 60 mA.(2)Other main parameters are shown in the picture.   (View)

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FET DC power amplifying circuit

Published:2011-7-13 20:04:00 Author:leo | Keyword: FET, DC power amplifying, Circuit

FET DC power amplifying circuit
Picture 1 shows a FET DC power amplifying circuit. VT1 is the difference amplifying circuit, while VT2 is the constant current differential circuit. And VT5 is electrical level moving circuit made by cascading amplifiers. The source voltage of VT3 is about 0.6 V and VT7 and VT8 are current mirror circuit which is used to aggrandize gain and improve the DC operating point stability. VT6 is the circuit that offers differential current to output terminal.   (View)

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A simple transistor test circuit

Published:2011-7-13 19:55:00 Author:leo | Keyword: Simple transistor test circuit, P channel FET

A simple transistor test circuit
As the picture a and b show, it is a simple transistor test circuit. The picture13(a) shows a FET test circuit. This circuit is mainly used to test FET pinch-off voltage UP and grid-source voltage UGS. In the circuit, VT is the FET to be tested, and A1 can form servo circuit whose output controls reversal phase input terminal potential and makes it become zero. Voltage-stabilizing diode VD3 and VD4 can produce voltage of±9V and clamp-on the grid potential of VT. R5 is the current limiting resistance which controls VT grid potential current and makes it under the set value. When S2 is connected to 1, VT grid potential voltage is higher than clamp-on voltage and A1 output is negative to the N channel FET while positive to the P channel FET.   (View)

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Chopper amplifer circuit made by TA7505

Published:2011-7-13 19:39:00 Author:leo | Keyword: Chopper, amplifer circuit

Chopper amplifer circuit made by TA7505
Picture 1 is a chopper amplifier made by TA7505, which contains a chopper circuit, synchronous rectifying and modulating circuit. The switch component of chopper and synchronous rectifier mainly adopts FET tube, such as VT1 (3SK38) in picture 1(a). This tube is a kind of FET tube which changes to stop state when the voltage is 3V(the maximum value). VT5 and VT6 can make up of multivibrator circuit which can generate the square wave voltage. The square wave voltage passes the trigger made by VT3 and VT4 to adjust the wave shape, after which the signals come to modulate the VT1 grid.   (View)

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The FET chopping amplifier circuit

Published:2011-7-10 2:20:00 Author:leo | Keyword: The FET chopping amplifier circuit, AC amplifier

The FET chopping amplifier circuit
Picture 1 shows a FET chopping amplifier circuit. Chopping amplifier is made up of chopping part, AC amplifier, and modulator and so on. In this circuit, 3SK38A(VT1 and VT2) is specially developed for FET with grid-source light current and small capability . It is enhancement mode component with the maximum voltage value of 3V. The multivibrator made up of VT5 and VT6 generates square-wave signals which pass through the trigger formed by VT5 and VT6 to be reshaped. After reshaped, the signals are added to the grid of VT1 to be modulated and the modulating frequency is 185Hz.   (View)

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The circuit diagram only permitting small DC singal voltage

Published:2011-5-20 19:56:00 Author:leo | Keyword: circuit diagram, small DC singal voltage

The circuit diagram only permitting small DC singal voltage
As what is shown in the picture, this is a circuit that only permits the small DC electronic current to pass through. If the inputting signal Ui is a sinusoidal waveform with the asymmetric peak value, and if the VFM is 11V and negative peak is -9 V, this waveform has small DC voltage. In some application, it needs to output the small DC signals and eliminate the AC signals which common low-pass filter cannot do but this circuit can make it come true. In this circuit, the buffer A1 buffers the inputting signals, and then the voltage of the buffered signals comes through the capacitor C1 and is coupled to a complete AC waveform voltage U1.   (View)

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The amplifer circuit formed by LM121 and used in device

Published:2011-6-8 21:08:00 Author:leo | Keyword: The amplifer circuit formed by LM121 and used in device, LM121

The amplifer circuit formed by LM121 and used in device
Picture 1 is an amplifier used in device. It is made up of LM121 and others. LM121 changes the differential input voltage into differential output voltage to drive the backdrop operating amplifier A1. A1 can form current-voltage converting circuit which change differential input to output. R1, R2 and RP1 are used to set the working current of LM 121 and regulate the imbalance current(voltage) of the circuit. While RP2 is used to regulate gain. They do not influence each other. The limited input voltage of LM121 is ±10mV, which can form higher common mode rejection ratio (120dB) and low drifting device amplifier.   (View)

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The high-speed absolute value amplifier circuit diagram

Published:2011-6-8 22:01:00 Author:leo | Keyword: The high-speed absolute value amplifier circuit diagram, LM318, HA2525

The high-speed absolute value amplifier circuit diagram
The picture 1 shows a high-speed absolute value amplifier circuit. The operating amplifier and diode form the ideal diode circuit which is used to detect communication signals. However, in the ideal diode circuit, rectified input voltage gives an effect directly to the frequency of operating amplifier and high frequency is limited. High speed operating amplifier, such as LM318, HA2525, μA715 and so on, can ensure an over 100kZ operating frequency. Operational Amplifier should be selected in the high-speed absolute value amplifier circuit. In this circuit, A1 uses HA2526 operational amplifier and also LM318. But the cut-off distortion of diode affects the high frequency operating, therefore, it takes VT1 and VT2 to form constant current source in this circuit.   (View)

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300B Vacuum Tube Single End A Type Power Amplifier Circuit

Published:2011-4-23 1:00:00 Author:May | Keyword: Vacuum Tube, Single End, A Type, Power Amplifier

300B Vacuum Tube Single End A Type Power Amplifier Circuit
300B Vacuum Tube Single End A Type Power Amplifier Circuit, vacuum tube has 12AX7 pdf. The frequency respondence of this amplifier is very flat, it only has ±1dB changefrom 18Hz~30KHz, total harmonic distortion of this amplifier is less than 1%.   (View)

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STK4121-2 Power Amplifier Circuit Diagram

Published:2011-4-1 2:44:00 Author:may | Keyword: Power Amplifier

STK4121-2 Power Amplifier Circuit Diagram
The STK4121-2 Power Amplifier Circuit Diagram is shown in the following picture:   (View)

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Bridge mode power amplifier circuit

Published:2011-3-21 0:56:00 Author:may | Keyword: Bridge mode power amplifier

Bridge mode power amplifier circuit
Bridge mode power amplifier circuit is show in the following picture:   (View)

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Power Amplifier uPC1280V Circuit

Published:2011-3-29 22:05:00 Author:may | Keyword: Power Amplifier

Power Amplifier uPC1280V Circuit
The Power Amplifier uPC1280V Circuit is shown in the following diagram:   (View)

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vacuum tube multipath audio mixing circuit 1

Published:2011-3-29 22:00:00 Author:may | Keyword: vacuum tube, multipath audio mixing

vacuum tube multipath audio mixing circuit 1
diagram:vacuum tube multipath audio mixing circuit 1   (View)

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Vacuum tube multipath Audio mixing circuit diagram 2

Published:2011-3-21 0:47:00 Author:may | Keyword: Vacuum tube, multipath Audio mixing

Vacuum tube multipath Audio mixing circuit diagram 2
diagram: Vacuum tube multipath Audio mixing circuit diagram 2   (View)

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Vacuum Tube single End A Type 211 Power Amplifier Circuit

Published:2011-3-21 0:39:00 Author:may | Keyword: Vacuum Tube, single End, A Type, 211, Power Amplifier

Vacuum Tube single End A Type 211 Power Amplifier Circuit
diagram:Vacuum Tube single End A Type 211 Power Amplifier Circuit   (View)

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