Voltlog #69 - LM317 Kit Assembly Fail

Sometimes, when I have some spare time I like assembling these cheap kits coming from China. Today I am assembling an LM317 adjustable power supply kit complete with voltmeter. Unfortunately they sent me a wrong resistor value so the kit didn’t work as expected but I was able to fix it in the end.
LM317 Adjustable Voltage Regulator Kit
Banggood: voltlog.com/y/u...
Ebay: voltlog.com/y/f...
Kester 186 Soldering Flux
voltlog.com/y/s...
Solder Wire
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Selection of soldering stations
voltlog.com/y/y...
Fume Extractor
voltlog.com/y/w...
Side Cutter
voltlog.com/y/4...

[@YouAllKnowBob]

Failures are learning experiences. Never be afraid to upload them and show us how you did the troubleshooting. Good video!

[@voltlog]

thank you!

[@pyotrleflegin7255]

Anything you learn from shouldn't be considered a failure, merely as a step along the path. Well done for trouble-shooting so neatly!

[@InterestsAll]

I just dug this kit up from my lost collection and it didn't come with assembly instructions. Thanks for the Video!

[@JohnGotts]

You got it working. Most software you use today has the equivalent of 1,000s of resistors with the wrong value, but it works well enough. That's why hardware is hard for me and software is easy. Defects are not such a problem.

[@voltlog]

that's an interesting comparison between software and hardware :)

[@MartynDavies]

The diodes are for reverse voltage protection. You quite often see this on regulator circuits that will be used to charge a lead-acid battery.

[@voltlog]

yeah, looking at the datasheet refreshed my memory. Thanks!

[@iceberg789]

thanks to the resistor hint, loled big time @ 10:50, " what kind of range is this !!?!! " :)

[@voltlog]

it was funny :)

[@englishrupe01]

Hi...cool video, thanks! Is it possible just to switch out the LM317 with an LM338 instead? Or does it need a lot more figuring out? I just bought myself a couple of these kits, but i hate to blow one up through my ignorance if i use LM338 instead. Thanks!

[@DeeegerD]

Always measure every component before assembly with any kit ;)

[@voltlog]

That's a good rule but I don't know if anyone follows it :)

[@DeeegerD]

VoltLog I do, better to find the fault before you assemble it all lol.

[@Zetex2000]

You can learn more about the protection diodes across the LM317 in the LM317 datasheet. Also, a basically silent fume extractor that I built is that I used a "fluid dynamic bearing" fan (any decent PC store carry those around, for me is cost about 10$ for a "arctic" one) and put those on top of a small box that includes 3 lithium ion batteries in series a switch and charging and protection circuit. all it is a silent fan connected to a battery with a switch, but if you add carbon filter (I think that's how those are called) you can filter out the smoke. and the reason I made it battery powered is so you can adjust it and move it everywhere without having a cord around your bench, I just hate wires, if there is a cordless option I would go for it.

[@voltlog]

I plan to build a fume extractor unit that would sit under my desk with adjustable speed. It will use a carbon filter ofcourse because without that you're just mixing and dispersing the fumes in the air around you.

[@softtechelectronics4554]

The dual pot is for mechanical stability

[@YUCRYN]

i have bought this same power supply from bang good and it claims to provide 12v but actually it doesn’t go beyond 6v

[@swan7654]

How much output current does this modal have

[@pollydor07]

THANKS . MINE I RECEIVED FROM ALIEXPRESS AND TRIED IT LM317 I GOT 13.50 V DC PLUS MAX

[@nor4277]

I don't no where you buy your kits at,but the kits from eBay hardly ever have a diagram or instrucktions.

[@voltlog]

Ebay and Banggood. There are always links in the description below the video.

[@timramich]

I don't get the R thing for resistors. Do people use C for capacitor values?

[@voltlog]

it's not just R, any letter marking can be used 1K5 = 1.5KOhm, 1M5 = 1.5MegaOhm. That's preferable to using the omega symbol Ω because that's not always easy to find and insert when editing schematics.

[@timramich]

VoltLog I know how it works, I just think it's weird. 220R is no shorter than 220(omega symbol). What do you do for capacitor values? Use C?

[@voltlog]

I'm talking about the somewhat difficult way of inserting the omega symbol when editing a schematic, it's much easier to write "R". For capacitors you usually specify them in "nF" , "pF" or "uF" just using "u" instead of μ mu symbol. It doesn't have to be a general rule if what's what you're searching, it's just an easier way of editing schematics.

[@timramich]

You don't even need the omega symbol. I just think it's dumb to write something like 1r2 or 1k2, instead of 1.2k.

[@simontay4851]

I just write the word ohm. R just doesn't look/sound right.

[@BIBIwood]

Do you have a Patreon page ?

[@voltlog]

I don't have a Patreon page yet, I might setup one at some point if people are interested in supporting this channel.

[@abdulkadermaqsoud4890]

Sir , thx for uploading , i'm always using for those Chinese kit instructions , my iPhone camera and google translate ap , please try it .

[@voltlog]

yes, that's a good method, I use it sometimes. Thank you for watching!

[@SidneyCritic]

So they gave you a 50K pot instead of a 5K, and a 10K resistor instead of a 240R, classic.

[@voltlog]

yeah, it happens with these cheap kits.

[@berghauss]

Actually, from your perspective this was a win, not fail.

[@voltlog]

correct :-)

[@brainndamage]

1k2 should work well with 25k, same ratio as 240&5k.

[@voltlog]

yes that sounds right.

[@hasany.748]

The 240R resistor is may be there for a reason. It may be a bias resistor for current source inside the chip. Before replacing parts in schematic even if the ratio is preserved, it better to look at the datasheet in advance.