Variable DC Power Supply for <$15
Intro: Variable DC Power Supply for <$15
Variable DC power supplies are critical to many electronics projects. You'll never have to go out and buy dozens of different single-voltage power supplies or battery configurations with this new unit. Professional units can cost hundreds of dollars, but now you can make one for less than $15!
STEP 1: The Parts
STEP 2: The Variable Voltage Regulator.
Start by making the variable voltage regulator. Refer to the schematics below.
STEP 3: Adding the Digital Readout
Adding the digital readout is really simple! Just open up your multimeter and solder your output to the test leads. Add a switch to the battery. And that's it! You're done :D
STEP 4: You're Done
Test it and have fun! Put it in an awesome enclosure like I did to impress your friends :)
70 Comments
tgvoss 9 years ago
Do this all for $5 http://www.ebay.com/itm/LM2596-Buck-Step-down-Power-Converter-Module-DC-4-0-40-to-1-3-37V-LED-Voltmeter/400802470941
WasimA22 7 years ago
it will burn out after 3amps
tgvoss 7 years ago
The power supply in this ible can only deliver 2.7A and the regulator can only handle 1.5A. Right?
Jonny124 10 years ago
I'm no expert but I think the max of the lm317 is the max of the power supply witch is also the max of the whole thing
ade almeida lopes 8 years ago
that goes for any buck converter that isn't also a boost converter.
darkath 8 years ago
The little leads that connect to the volt meter, what are they called?
stewie0056 13 years ago
would you care to explain that for me?
one more thing. would a tl780-05c voltage regulator work?
DraakUSA 9 years ago
If you have a 3 pin pot, attach the wiper to the upper leg, the same leg that attaches to pin 1 of the LM317.
mrmerino 12 years ago
royshearer 12 years ago
Dwmiller717 12 years ago
francoisvans 12 years ago
This is a very cool instructable! I already bought all the parts, except for the capacitors. I am quite a novice with electronics so please be patient… :)
“0.1 uf Mylar Cap (~$0.10)” – Is this 0.1 uf Radial Electrolytic capacitor? In the pictures included in the pdf file it is a 0.47 uf 50v capacitor, will this also work?
“1 Axial Electrolytic Cap (~$0.20)” – In one of the comments “silencekilla” said that is should be a radial capacitor, is this correct and what should the value be? 1 uf ?
Thanks
Electronics Man 12 years ago
Electronic hacker 13 years ago
the links are broken so i cannot see :(
and also would the resistors regulators and such change if i were to use a different voltage power supply?
(sorry i do not know the purpose of these things and what they do)
LM317 Voltage Regulator ($0.50)
0.1 uf Mylar Cap (~$0.10)
1 Axial Electrolytic Cap (~$0.20)
220 Ohm Resistor (~$0.05)
thanks in advanced
FreeHighFives 13 years ago
burzvingion 16 years ago
rcisneros 13 years ago
Dr_Acula 16 years ago
wii552 13 years ago
silencekilla 13 years ago