I have designed a symetrical PSU using LM317, LM337 plus power BJTs. The desired output range is at least 24V-2V @ 6A max. Altough not shown in the schematic, i plan to add power resistors and a rotary switch to provide current limiting. What do you think about it? Is there some better way of limiting current, without high power pots, JFETs and resistors? schematic

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    \$\begingroup\$ With 6A the Cap ripple current rating may be exceeded greatly. Also dV=10ms* 2A/ 4.7mF=4V decay on peak input \$\endgroup\$ – Sunnyskyguy EE75 Jul 14 '18 at 21:48
  • \$\begingroup\$ That's okay, the voltage would be 28V, still over my reqiurements. \$\endgroup\$ – thegamebusterpl Jul 14 '18 at 22:08
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    \$\begingroup\$ Your transformer says 12-0-12 so you'll be lucky to get +/-9V out of it at a few A. P-P ripple will be 0.05*6A/0.047F = 6.3V, plus a diode drop plus the drop across your LM317 etc. plus a drop across the pass transistor (that gets you down to a few volts out). Also pay attention to Tony's comment about ripple current rating or your capacitors will die early. \$\endgroup\$ – Spehro Pefhany Jul 14 '18 at 22:17
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    \$\begingroup\$ What do I think of this design? I think it is about 40-years antiquated (LM317 was introduced in 1976). It is generally recognized that electronics design and component base changes about every 5 years to an extent that requires re-training of electrical engineers. So this design is about 8 generations behind. What would be a reason to live in such deep past? I know it is not nice, but truth should be told. \$\endgroup\$ – Ale..chenski Jul 14 '18 at 23:30
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    \$\begingroup\$ @thegamebusterpl - You should listen to yourself more closely. "around 33V peat with no load" Right you are. But then you go and spoil the effect by talking about a 6 A output. See the problem? (And yes, you may now facepalm. But don't worry, we all do at first. If you're any good the rate will go down with experience.) \$\endgroup\$ – WhatRoughBeast Jul 15 '18 at 13:25

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