A shout-out for Phil at Jumper1 - plus a nice LM317 PSU project

[nzo]

Phil's electronic projects and presentation are beautifully done with a lot of care. His tutorial videos are excellent. If he finds all is not as it should be at the end of a project, he goes back and fixes it and tells us what he did and shows us how. The world could do with many more like you Phil. Good on you mate!

Check out his vids and notes on an LM317 Adjustable Power Supply

Jumper1

[johnboxall]

Fantastic, thanks for that 

[phil_jp1]

Thanks! But my tutorials are far from excellent. There's a lot of room for improvement.

- Phil Levchenko

[patb]

Thanks for the tutorial. Ive just subscribed to Phil's youtube channel. :-) Waiting for the next video.

Patryk.

[shebu18]

Great tut, i also build these day a LM317 power supply. The other tuts are also great.

[Zero999]

Hi Phill,
Did you try using better resistors for the potential divider? It's possible simply replacing them with 1% metal film would've solved the problem without having to rebuild the PCB.


A relay is an interesting solution to the voltage drop problem. Another solution would've been to simply put the switch before the LM317 which will compensate for the voltage drop.

[phil_jp1]

Hi Phill,
Did you try using better resistors for the potential divider? It's possible simply replacing them with 1% metal film would've solved the problem without having to rebuild the PCB.


A relay is an interesting solution to the voltage drop problem. Another solution would've been to simply put the switch before the LM317 which will compensate for the voltage drop.

Yeah, 1% metal film resistor could've solved the problem, but I wanned to put another output cap anyways, so I've decided to make things right. )

Switch before LM317 - in this case it's not an option. Because 1. pretty big output cap won't discharge immediately. 2. output protection diode might be a problem in some cases. Anyways it's better to physically disconnect the load.

[ciccio]

Switch before LM317 - in this case it's not an option. Because 1. pretty big output cap won't discharge immediately. 2. output protection diode might be a problem in some cases. Anyways it's better to physically disconnect the load.

Yes, you are correct: the switch must be at the output side...
If the load is small, the capacitor could keep the output live for a long time.

Keep up with the good work.

[Zero999]

There is another solution to the problem: an SPDT switch could be used with one set of contacts discharge the capacitor via a resistor when it's in the off position.

[phil_jp1]

There is another solution to the problem: an SPDT switch could be used with one set of contacts discharge the capacitor via a resistor when it's in the off position.

But what if this power supply would be connected to battery or big capacitor bank? That battery or capacitor bank will be discharged through that resistor.
Normally it's better to just find an appropriate load switch with small load resistance.