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I want to make a Lm317 4.5a output circuit. So I want to know that- do I need any resistor on point 3 & 4? And which capacitor will be best for point 1 & 2. Pls help me. enter image description here

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    \$\begingroup\$ See page 16 in the TI datasheet for LM317. \$\endgroup\$
    – The Photon
    Commented Apr 5, 2018 at 5:29
  • \$\begingroup\$ I don't have all components from datasheet. Pls help me what I asked for. \$\endgroup\$
    – Suny
    Commented Apr 5, 2018 at 5:40
  • \$\begingroup\$ Lacking components, use one LM317 in the short shoulder (KCS) variety of TO-220 and clamp its bottom side to a big cooler looking like this: images-na.ssl-images-amazon.com/images/I/… \$\endgroup\$
    – jonk
    Commented Apr 5, 2018 at 6:11

2 Answers 2

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Here is the circuit you should be using from the LM317 data sheet! You'll notice your resistors at 3 and 4 are there to protect the individual supplies from slightly different outputs.

In this example they're using an OP Amp to set the adjust voltage but you could actually just set them all the same (with fixed resistors) assuming you don't want it variable.

In any case you'll need a nice big heatsink to get this much current out of the chips. Id suggest using a large metal plate if you've got nothing else.

Hope that helps! enter image description here

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  • \$\begingroup\$ Only the last lm317 getting hot. Is that normal? \$\endgroup\$
    – Suny
    Commented Apr 7, 2018 at 2:45
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Have a look at the first circuit in LM317 High Current Voltage Regulator

Naturally TI prefers you to buy more TI circuits, but this solution is simpler and cheaper => better.

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