Simple adjustable power supply on three LM317 chips

Hello, today I will tell you how to make an adjustable power supply unit based on the lm317 chip. The circuit will be able to issue up to 12 volts and 5 amps.

Power supply circuit diagram



For the assembly, we need


  • Voltage stabilizer LM317 (3 pcs.)
  • Resistor 100 Ohm.
  • Potentiometer 1 kΩ.
  • Electrolytic capacitor 10 microfarad.
  • The ceramic capacitor 100 nF (2 pcs.).
  • Electrolytic capacitor 2200 microfarad.
  • Diode 1N400X (1N4001, 1N4002 ...).
  • Chip heatsink.

Simple adjustable power supply on three LM317 chips

Circuit assembly


We will assemble the circuit by mounting, as there are few details. At first we attach the microcircuits to the radiator, so it will be more convenient to assemble. By the way, it is not necessary to use three LM. They are all connected in parallel, so you can do with two or one. Now all the extreme left legs solder to the potentiometer leg. To this leg we solder plus a condenser, minus we solder to another outlet. To prevent the capacitor from interfering, I rewired it from the bottom of the potentiometer.
Simple adjustable power supply on three LM317 chips

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

To this leg of the resistor solder the diode. To the other leg of the diode solder all the right legs of the chip (I have white wires). Plus we solder one wire, this will be a plus 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 a minus of entry and exit. 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, plus and minus the output of the capacitor at 100 nF (100 nF = 0.1 μF, marking 104).
Simple adjustable power supply on three LM317 chips

At the entrance, we solder a 2200 microfarad capacitor, the positive leg is soldered to the positive input.
Simple adjustable power supply on three LM317 chips

At this production circuit is ready.
Simple adjustable power supply on three LM317 chips

Since the circuit produces 4.5 Amps and up to 12 Volts, the input voltage should be at least the same. We will adjust the output voltage with a potentiometer. For convenience, I advise you to put at least a voltmeter. I will not do a full body, all I did was to attach a radiator to a piece of fiberboard and fasten a potentiometer.I also brought the wires out and screwed crocodiles to them. This is quite convenient. Next I attached it all to the table.

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