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Variable Voltage Regulator - Filtered Linear Power Supply

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This Instructable will show how to Make a 1.6v-6v Filtered Linear Power Supply using a LM317 for the variable voltage regulator and a 1kohm Potentiometer (trimmer). It can source power from anywhere between 7v to 14v for this version of the power supply. The power supply in the above image is at the top and you can see a 7.4v battery plugged into it, with a 3.3v cable harness attached to the output on the right of the power supply.

Filtered means that it is good for sensitive IC's as it will provide the most accurate selected voltage possible. This is accomplished by using filter/bypass/decoupling capacitors on the power rails to reduce noise. This power supply can source power from a range of power supplies within 7-14 volts @ 500ma. The lm317 can sink more than 500ma of current but at the sacrifice of having to use a lower voltage, this is because the LM317 has a max rating of 3watts total. Sinking 1.5 watts of power uses a fair size heat sink so if you want to have more power running though it you may want to move to a larger Voltage regulator.

This power supply is not suited (or needed) to power standard MCU's like the arduino uno or mega. It works great with a few tweaks to power a stand alone or breadboarded ATMEGA328 though, because the power is filtered and you have a nice easy way to adapt it to the same sources the standard arduino's use. Just beware that the ATMEGA328 is capable of drawing up to 560ma with just it's digital pins and this will stress the heck out of the power supply.
 
 
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_Scratch_3 years ago
Anyone know where i can get a 12v to 5v DC power supply that can handle 10 amps?? I've been looking everywhere, i cant find one.
Does it have to convert 12VDC to 5VDC? Or does it need to be adjustable from 5-12VDC? The big linear project I put on this site could do either, but is not the best method if you're looking for the first 12V to 5V scenario. Then I'd just use a 7805 with a big pass transistor on it.

Something like this but go bigger on the pass transistor. I think a 2N3055 can push 10 amps.
shams3 years ago
Hi......could u publish an instruction about your transmitter ?

Oh another thing for higer amp u can use power transistors with lm317
pfred2 shams2 years ago
I just put up a bypass transistor linear supply on this site but it doesn't use the 317 it uses the 723. I think right now my supply is the reigning champ of the site heh. It's a monster!
Poent (author)  shams3 years ago
Sure I'll take some pictures and set up the instructable for the transmitter. If you want informed when I get the instructable up you can click "follow" under my user profile and it should automatically inform you once it's uploaded.
Mdob Poent3 years ago
That would be great if your could publish and instructable for your transmitter!
jammit3 years ago
You have the 330 ohm and the 1K trimmer swapped. Put the 1K trimmer between ADJ and ground, and the 330 ohm between Vout and ADJ.