Power supply 4.5 A with 3 LM317 in parallel

4,5 Amperes power supplyThis lm317 variable power supply can supply a voltages from 1.2V to 30V with a current 3 amperes, just as the title of this series based on LM317T voltage regulator, the LM317T regulator provide around 1.5 amperes on the heatsink, so by installing a parallel two or three of them will get a voltage source capable of providing 3 amperes. Obviously this also depends on the transformer used.


TheLM317T regulators are able to withstand short circuit at the output of the source and not so easily destroyed like LM350K or LM338K regulators, the regulator IC used in this circuit using ST manufacturing company and have shown positive result.

Note before assembling:

  • Make sure the transformer is to provide currents as on the label.
  • Regulators should be installed on aluminum heatsink very nicely.
  • Although the source has a short-circuit protection and over-consumption, it depends on the size of the heatsink, because when this error occurs, the temperature emerges, and it is best not to give short for fun.
  • When a short circuit occurs Power LED will be slightly decreased in brightness, but the best thing would have a voltmeter to display these errors.


Tags: 4.5 ampere lm317 variable power supply LM317T regulator LM317T voltage regulator variable power supply

Related Post "Power supply 4.5 A with 3 LM317 in parallel"

12V / 3A Regulated Power Supply
Here we provide a powerful 12V /
Bench Power Supply Adjustable 1.25V-15V and Fix 5V
This is bench Power Supply give you
1.2V – 57V Regulated DC Power Supply Circuit
This is the circuit diagram of multi
1.5A Negative Adjustable Power Supply
This is the circuit diagram of negative
  1. author

    John Gjertsen4 years ago

    Could someone propose a heatsink suitable for this supply. I have paralled two Radio Shack transformers which give me 12.5 and 25 v ac at 4 amps which could be used for input. I am looking for 20 vdc at 3.5 amps max for only one particular application. Other voltages and amps would only be frosting on the cake and nice to have. Thanks in advance

  2. author

    Anon2 years ago

    Wrong way to do it, see the data sheet for the right way.