Adjustable Power Supply Experimental 3AG1 Kit 0-15V 0-5A Regulated Constant Current LM317 | Бытовая техника

Adjustable Power Supply Experimental 3AG1 Kit 0-15V 0-5A Regulated Constant Current LM317 | Бытовая техника

Power SupplyDIYRequirements for comprehensive electronic capabilities are high，

Our shop can not provide comprehensive technical support，Please also take cautious pictures.！

Please also weld carefully and carefully.，Component polarity must not be reversed，Especially large electrolysis！

First power on as far as possibleAway from motherboard！ Preventing all kinds of welding errorsElectro-liberation Gun Incident！！！

Power transistor IRF3205 Transformer12-15V 75WOf（Disassembly with power amplifier）

If the current reaches5AThen the power transistorIRF3205Need large radiators（CPUOr the power amplifier can do it.)

Can not be installedLM317Fancontrol circuit Increasing the heat dissipation area of the adjusting tube will do.。

IRF3205Can be used75NF75, Other models of high power can also be used.NMOSField tube。The on-resistance should be as small as possible.。

3AG1One of the Classic Designs of Teachers

1.C3,C4,D1,D2Voltage doubling rectifier,provideMOSDriving High Voltage.

2.Q1,R1,D3,D4Constant current source,Constant current approximation7mA,provideMOSDriving current.; T. D7 M8 p+ f) V! E4 @( q-

3.LM317Circuit-driven fans.% c X* K* {! S; C! z

4.LED1,Q2,R4Constant current source,Constant current approximation5mA.

5.R6,R7,U1Stable Voltage5V,Power supply as control circuit

principle：TL431 See it as a self-contained2.5V Voltage Reference Operational Amplifier with Inverse Phase Output，And yes.OC Output mode,Complementary Output Different from Ordinary Operational Amplifier。U1 Join5V Voltage reference，U2 Amount to2.5V Precision regulator，BecauseTL431Used as a voltage comparator，His threshold voltage is high.，stay2.45 ~ 2.55V between，So useU2 Weak Signal Voltage on Lift Galvanometer Resistance。U3 andQ3Constituting current stabilizing control circuit，When the load current tends to increase，Galvanometer resistanceR0 Increased pressure drop，U3 It tends to be conductive.，throughQ3Reverse phase output high level，On the one hand, throughLED2 As a steady flow indicator，The other is to addU4 Adjustment endR，sendU4 OfK End Output Voltage Reduction，Adjusting pipeIRF3205The output voltage also tends to decrease.，To maintain load current stability。Through controlU4 Adjusting terminal voltage，It can adjust the output voltage or set the output current.。

The circuit diagram is as follows.：

（If you use a digital header，There is also a need for a set of power supplies to the meter head.，If there is no suitable winding on the transformer，

A small transformer can be added to power the watch head.。

Digital meter head consumes less power，When the working current is relatively stable，It can also be used in the circuit.5V Voltage as Head Power Supply。

This needs to be reduced.R4，EnlargeQ2 Output current。）

Add voltage、Behind the Head of Current Indicator，You can debug the power supply.：

1. First adjust the output voltage to 5V，Current-regulated potentiometer set to the lowest current，Wire Short Connection Output

（Digital multimeter is also available200mA The current stop is connected to the output terminal），adjustVR3 Minimize the output current。

2. Remove the short wiring at the output end of the power supply（or200mA Multimedia Line），

Careful callbackVR3 To restore the output voltage to the voltage before short connection，The minimum steady current will be adjusted.。

PCB：size10*5CM

Note that the positive and negative poles of the light emitting diodes are based on the in-frame markings.！

Component foot length plus or minus。Semi-circular screen printing is reversed！

 Pay attention to the positive and negative poles of light-emitting diodes. The length of the element is short and negative. The semicircle screen printing is wrong!

Two boards in series，Make a public place in the middle，It can form positive and negative power supply.，No tapping is the highest output30V Adjustable power supply。

This is the reference wiring diagram after matching other peripheral devices.：

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All of the kits：（Self-Welding of Full Bulk Parts）

change18VTransformer，In the circuitR15 Change to16K，The other is enlargement.R9Resistance value，Make the maximum output current of the power supply at3AAbout，Don't overcharge the current.，Preventing Field Tube from Overheating Burnout。The maximum output voltage after the modification is about 1.18V。