what do with a lm317t regulator - Page 1
Forum section: electronics / projects

author: Arcamax
author_rank: Regular Contributor
timestamp: February 03, 2015, 02:45:52 am
content: I need to make something with one of these lm317t's cause i have six of them. So i need some ideas please.

author: digsys
author_rank: Unknown
timestamp: February 03, 2015, 02:53:26 am
content: First, go to any (or all) of the Manufacturers (many) pdfs and look through their suggested applications.Some have HEAPS of ideas !!

author: c4757p
author_rank: Super Contributor
timestamp: February 03, 2015, 02:57:09 am
content: Save them for when you have a reason to use them?

author: Arcamax
author_rank: Regular Contributor
timestamp: February 03, 2015, 04:09:38 am
content: i know i can use it make a simple adjustable power supply. but what else.

author: c4757p
author_rank: Super Contributor
timestamp: February 03, 2015, 04:12:41 am
content: Save them! Use them as regulators inside something else you might build.Failing that, assemble them into a small sculpture of an LM317T.

author: Arcamax
author_rank: Regular Contributor
timestamp: February 03, 2015, 04:23:48 am
content: Quote from: c4757p on February 03, 2015, 04:12:41 amFor oneIve had them for a while and i was trying to make a solar phone charger but now i might use a adjustable dc step-down buck converter... so i need some thing to use these for.

author: Alex30
author_rank: Regular Contributor
timestamp: February 03, 2015, 04:32:09 am
content: I always buy regulators and other components and then realise I need something else before they even arrive. They just all go in my drawers and now I have a pretty decent collection. Regulators are always handy for almost any project you want to build.

author: Circlotron
author_rank: Super Contributor
timestamp: February 03, 2015, 05:04:22 am
content: Make a class A audio amplifier out of one! I cooked one up in 2003. See pic. They are actually a power amp after all.The quiescent current is set by 1.25 volts divided by (in this case) 1.2 ohms for about 1 amp. 14 volts supply is car battery voltage. You may need a 10 ohm resistor in series with a 100nF cap across the inductor just to make sure it is stable in all circumstances. It worked ok without it but I'd feel more comfortable with it. Anyway, voltage gain is load resistance divided by bottom resistor, so 1 volt peak will drive it just nicely. That's fairly average for most power amplifiers. I fired it up briefly tonight and fed it from the PC sound card speaker output and it sounded quite respectable considering what it is made from.So there you go. Probably the worlds simplest low distortion thermally stable true class A power amp using what really amounts to a single ended power amplifier chip. It costs next to nothing and takes about 5 minutes to wire it up point to point. The only tricky part is the choke. Must have a gapped iron core and be able to handle 2 amps without saturation.

author: AG6QR
author_rank: Frequent Contributor
timestamp: February 03, 2015, 05:25:09 am
content: With the addition of a single resistor, it makes a reasonable constant current regulator. See the data sheet. They can be used that way for safely (but not terribly efficiently) driving an LED from a widely varying voltage. Or if you get a BCD digital switch and a bunch of resistors, you can create a constant current load which can be set to a precise value by rotating the digital switches.Here's a plan for constant current regulator:http://www.instructables.com/id/A-simple-4-channel-adjustable-current-source/I made something like this, but mine was only one channel, with two thumbwheels, for two digits of precision. And mine has no power supply in it; it's just a current regulator with + and - banana jacks. I can put it in series between a voltage source and a load, or I can use it for tests of batteries and power supplies without any additional load.In standard constant-voltage mode, I retrofitted one into a clock which I wanted to install in my camping trailer. The clock was designed for battery power, but I wanted to power it by the trailer's 12V electrical system, so I wouldn't have to worry about changing the clock's battery. You may think of some similar hack if you want to power a small low-current device from some sort of source that it wasn't originally designed to use.

author: babysitter
author_rank: Frequent Contributor
timestamp: February 03, 2015, 05:44:42 am
content: Try to do something with them what is normally unwanted: Make a power oscillator! Maybe you can get it up to the long-wave AM band and do amplitude modulation, then you can replace one of the dyeing broadcast stations there.

author: Circlotron
author_rank: Super Contributor
timestamp: February 03, 2015, 06:24:45 am
content: ^^ LM317 response starts to roll off at about 40kHz IIRC. Have a look at the ripple rejection vs frequency to get an idea if it will have enough gain as an oscillator at the frequency you want.