Ok cool thanks IanB. Having said that Dave did mention you could do that in his psu video. It's embarrassing but at least I understand now and I won't have a small fire. My desk is very very very bad place to start a fire. Full of pieces of paper and other combustibles like IPA. Not to mention I would tarnish my pretty breadboard I got for free.
You really should consider moving those things. Put the combustibles where they won't combust. I wouldn't worry about paper, though it's probably best not to keep huge piles of it all over. Get the IPA the hell away from the burning resistors!
come to think of it it's a zero resistance so there nothing there to stop the current ROFL. I guess this was a dumb question LOL. But my mentor once told me there are no stupid questions, only stupid answers.
No, that's the wrong quote. It's: "There are no stupid questions, only stupid
people."
However I got the idea from a critical mistake I made in my lm338 based psu. I whipped together a psu with 4 fixed voltage ranges using rotary switch to switch in a different R2 value. I was sick of buying 9v batteries!! not expensive but just a pain to have move my lazy ass. I know it seems like a hack and dumb idea but I couldn't really afford a bench supply because I'll get my head bitten off and still do even though it's money I've earned as a programmer.
Anways I ASSUMED that my output capacitor couldn't store a charge big enough to heat up the 1/4 bleed resistor. STUPID I KNOW. Luckily my mentor noticed it whilst I was soldering it together and gave me a 0.47ohm 5w resistor to put in series.
Nah, an LM338-based PSU isn't a dumb hack, it's a good project for a beginner IMO. Lots of places to make mistakes (you see a stupid mistake, I see an educational mistake) but it's not so challenging that it requires experience.
Dude, quit insisting you're being stupid! This is how we learn. You toast a few resistors here and there, maybe vent a cap or two, and eventually learn to be careful. Want me to send you the corpses of my burnt resistors as evidence? I'm sure I can find a few...
I'm not so sure why your mentor had you install a 0.47ohm 5W resistor in series with a bleed resistor, though...... compared to the higher resistance of a bleed resistor, that might as well be zero.