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Hello, today I will tell you how to make an adjustable power supply based on the lm317 chip. The circuit will be able to produce up to 12 volts and 5 amperes.
Simple adjustable power supply on three LM317 chips

Power supply circuit


Simple adjustable power supply on three LM317 chips

For assembly we need


  • Voltage stabilizer LM317 (3 pcs.)
  • 100 ohm resistor.
  • Potentiometer 1 kOhm.
  • Electrolytic capacitor 10 uF.
  • Ceramic capacitor 100 nF (2 pcs.).
  • Electrolytic capacitor 2200 uF.
  • Diode 1N400X (1N4001, 1N4002 ...).
  • Heatsink for microchips.

Simple adjustable power supply on three LM317 chips

Circuit assembly


We will assemble the circuit by hinged installation, since there are few details. First, we attach the chips to the radiator, and it will be more convenient to assemble. By the way, it is not necessary to use three LMs. They are all connected in parallel, so you can do two or one. Now we solder all the leftmost legs to the leg of the potentiometer. Solder the plus of the capacitor to this leg, minus the solder to the other output. So that the capacitor does not interfere, I soldered it from the bottom of the potentiometer.
Simple adjustable power supply on three LM317 chips

To the potentiometer leg, to which the left legs of the microcircuits are soldered, we also solder a 100 Ohm resistor. We solder the middle legs of the microcircuits to the other end of the potentiometer (I have purple wires).
Simple adjustable power supply on three LM317 chips

We solder a diode to this resistor leg. We solder all the right legs of the microcircuit to the other leg of the diode (I have white wires). Plus solder one wire, it will be a plus of the input.
Simple adjustable power supply on three LM317 chips

We solder two wires to the second output of the potentiometer (they are black for me). This will be minus entry and exit. We also solder the wire (I have it red) to the resistor where the diode was previously soldered. This will be a plus exit.
Simple adjustable power supply on three LM317 chips

Now it remains to solder to the plus and minus of the input, the plus and minus of the output along the capacitor at 100 nF (100 nF = 0.1 μF, marking 104).
Simple adjustable power supply on three LM317 chips

Following the input, we solder the capacitor at 2200 μF, the positive leg is soldered to the plus of the input.
Simple adjustable power supply on three LM317 chips

On this, the manufacture of the circuit is ready.
Simple adjustable power supply on three LM317 chips

Since the circuit produces 4.5 amperes and up to 12 volts, the input voltage should be at least the same. The potentiometer will already regulate the output voltage. For convenience, I advise you to put at least a voltmeter. I will not do the full body, all I did was attach the radiator to the fiberboard segment and screw the potentiometer. I also pulled out the output wires and screwed crocodiles to them. This is quite convenient. Next, I attached it all to the table.
Simple adjustable power supply on three LM317 chips

Simple adjustable power supply on three LM317 chips
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Comments (6)
  1. Sergey K
    #1 Sergey K Visitors March 2, 2018 10:55
    3
    I would not have hoped too much for such a power supply. A parallel switching circuit is possible, but at least a 50 percent power margin must be left - microcircuits, even of the same series, even modern ones, all have a wide range of parameters. And in the case of power exceeding the power of an individual microcircuit, some of them will work at the limit, and maybe with overload, and eventually fail. Well, if only the stabilizer! Or maybe the powered circuit barks ...
    If you really need a current of 5A, can it be better to use the LM338? Or unsolder from old motherboards LM1083 (7.5A) or LM1084 (5A)
  2. Guest Andrey
    #2 Guest Andrey Guests March 2, 2018 12:40
    5
    That specialists in electronics already do not know how to draw electrical circuits.
  3. Guest Vlad
    #3 Guest Vlad Guests March 2, 2018 13:30
    2
    I circle one transistor and amperage then for more it turns out well, in general, for an amateur
  4. Guest Sergey
    #4 Guest Sergey Guests March 4, 2018 11:01 p.m.
    8
    Just quiet horror. The author would do it for himself slowly, and publish such a shame. Before publication, I would have looked at how variable resistors are indicated in the diagram. This design at a current of 4.5 A is likely to burn out, since no measures have been taken to equalize the current through the stabilizers. And if it doesn’t burn, consider yourself lucky - the built-in protection worked. In addition, for an output voltage of 12 V, the input must be at least 1.5 V more.
  5. Guest Nikolay
    #5 Guest Nikolay Guests March 29, 2018 02:59
    2
    Spread in a network SUCH? I am ashamed! It requires a current that exceeds the capabilities of the stabilizer microcircuit - add a powerful transistor and a 6-10 ohm resistor. The transistor and microstabilizer-on radiators are both simpler and more reliable.
  6. Guest Oleg
    #6 Guest Oleg Guests February 19, 2019 12:17
    0
    The author does not listen to anyone, ashamed there is not ashamed to someone. Laid out and well done. I support your starting.

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