LM317 based buck converter
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- Опубліковано 23 лип 2024
- LM317 based buck converter
LM317 DC-DC Buck Step Down Converter 5V-40V To 1.2V-37V: goo.gl/7wiCd2
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Me: Paul, 49 from USA
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That’s a linear voltage regulator and the multi-turn pot is installed in reverse. Buck/Boost converters are switched mode regulators. BIG difference here.
Not a buck converter lm317 is a linear regulator
I wish I could come up with a buck converter. That converted bucks to $10's & $20's! Great video.
This is my all day used Linear Regulator LM317 and its good for building custom power supplies, less noisy
Thank you for the demo of the LM317 type. I read something a while back that the LM317 has low ripple. I'm going to get a few and experiment with the different types. They must have the pot in backwards.
How the converter starts working. What just u do with that plz let me know that sir
lm317 has low ripple and noise and is good for powering microcontrollers, although it gets hot with a large Vin/Vout difference. The converter is quite noisy, but has better conversion efficiency. That's why I use a combination of both.
The LM317 is a popular adjustable positive linear voltage regulator. It was designed by Bob Dobkin in 1976 while he worked at National Semiconductor.
Thanks Paul. I recently bought the exact same on a ebay auction for US $0,57.
Do any of the modules your testing have the current limiting pot as well? These are really useful for testing etc!
I bought one of these regulators and could not get the output voltage to go below the full 24v of the input. I thought it was the pot. I turned it many, many times in each direction and nothing change. I pulled it out and put in fixed resistors, thinking the pot was bad. Still had full voltage. While the pot was out, I noticed that two legs of the LM317 were made poorly and that the metal coating the legs had formed a bridge. I broke the bridge with a small screwdriver and everything worked fine. I should have realized it would be something like this since the parts on the board were not mounted squarely and there are only a half dozen parts to begin with. Moral of the story is that these $1 regulators are low quality and use low quality parts and the whole thing needs to be gone over for manufacturing and assembly defects. You'd think that the person putting it together would have seen the bridge, but if I'm paying $1 shipped, they're obviously not putting much effort into the build.
How well would a buck converter work for running a DMR hot spot off a 12 volt battery? I'm looking to power my meager ham shack off a solar panel and a 12 volt battery. My HT chargers take either 12V(x2 chargers) or 10V(x2 chargers). The Jumbo spot is a RPi 0 W with the MMDVM Hat and a cellular hotspot both running at 5V. My guess(plan) is to run the 12V chargers direct from the battery, the 10V chargers through a buck converter and both 5V units off a second buck converter. Thoughts?
It will absolutely work. You will want the most efficient converter I'm sure. I have two more coming in. When they all are here we will test them and see which one works best.
Thanks, Paul, I'll keep watching, learning and enjoying your videos!!
What about the regulators voltage drop. is that 3v? If so, you need 15v to get 12v. not 12v from the battery. So where am i going wrong here?
Had this same experience with trimmers on Chinese voltage converters. Got to run them 10 turns to their extents before they click and hook in! The same trimmers, when purchased as individual components, do not have this problem, and are preset at about mid-range.
That's interesting. I think they are all manufactured in the same factory. Why would some be set differently?
I was betting on a bad pot. So many turns, because the Chinese think on more levels than we do? It'll be interesting to see the shootout because I'm in the market for a couple Buck Converters. Thanks, Paul you make the best teaching electronics videos out there!
How just u solve the probleb plz let me know
I have built power supples using LM317's driving power transistors on huge heat sinks. As soon as you get a large difference in the volts in and out they get very hot i.e. around 100 watts going from 36V to 12v at 4 amps. Buck converters are about 80 to 90 % efficient and run a great deal cooler. Buck's are said to be electrically noisy. You are sitting right next to one in your computer power supply reading this and it's driving a processor that's very, very fussy. By the way there is a surface mounted rersistor normally known as 'R1' between the cap and the pot. The little heat sink is useless - unless you want to light a cigarette.
I have around a thousand of those tiny POTs for my tinkering projects, and I’d bet a dollar to a doughnut that only 700 or so actually work. Lol Good video!
It's a linear regulator → terrible efficiency at high voltage differential and / or high current
Great follow up Paul, thank you - I have some buckies on the way! Rude not to as they are less than a buck... 🤑 🤪 🐍
That's not a buck converter! Useful, but not in any way a buck converter, it's a linear regulator. I clicked on this video thinking that someone had done something crazy that involves the LM317 being used in an unusual way.
I got these also :)
Awsome, sorrybwould write more but have broken hand.
Hey this is a linear regulator. Not buck regulator.
Yes I know. But it is being sold on ebay as a buck converter. I bought a number of different ones. This one is as you said an LVR.