Video- LM317 Adjustable Voltage Regulator Tutorial

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This video shows you how to build a regulated power supply using LM317. This post is a supporting article to the following posts:

This video does not belong to BuildCircuit.

You can purchase a simple ‘breadboard power supply using LM317’ at buildcircuit.net. www.buildcircuit.net is an online store operated by BuildCircuit team.

try this also

80 COMMENTS

  6. i would like to create voltage regulator of 0-50v range…can i use the
    lm317?? and do you know any software wherein i can check it,,i use circuit
    wizard but i can’t find the lm317 on the software

  8. Can I use 2 SMD electrolytic capacitors with these ratings (0.1 and 1)
    instead of one ceramic and one standard electrolytic? Thanks for your
    answer.

  11. If you want the cleanest “audiophile” power, run off batteries. If you want
    to make this circuit have minimal noise, increase C2 to 1000µF or more.
    (Note, if you increase it a LOT, the output voltage will take a while to
    get from 0V up to the set voltage. This MIGHT cause unusual sounds during
    power on. I don’t think it will ruin your device, but I won’t guarantee
    that!)

  12. sir i have one question i got something like a potentiometer from a mouse
    it was placed in the mouse wheel can you tell me if that is a potentiometer
    or is that any other device

  13. Is there any way to create an adjustable voltage supply from 0 to 25V ?
    Because I had a teacher who told us that is possible, but he never showed
    us how…. (sorry about my bad english)

  15. is there any way to split a dc source. like making two 5 and 7 volt sources
    form a 12 volt source. and thanks a lot for these awesome vids… you rock
    m/

  17. whats the maximum amperage rating for this? I need to convert 12v (or
    rather, ~13.6v) DC to 16-18V @ 18-20amp max. how do i increase the maximum
    amperage rating? the input voltage would be off a car battery/running car
    voltage.

  20. i dont understand the math … =( do you know of any books where i can
    learn the basic formulas? cause right now i just been getting schematics
    and putting things together but i have no understanding of the math behind
    any of the project i do

  23. Kinda. What you really want to do is have 1 transformer with multiple
    windings on the secondary side to give you the multiple voltages.

  24. Hey, great video. I have a question you may be able to help with. I’m doing
    an RC wheel chair mod and I need to get a 6v power supply to output 2.5v
    positive AND 2.5v negative. Using the LM317 and various resistors i’m able
    to get the positive current right in the butter zone but the negative is
    always around -3.8 or so. Would you have any suggestions on what I would
    need to regulate the negative current and how to do that? Thanks!

  29. Great vid, but you can avoid using thi specialty reg and use regular 7805,
    7809, 7812, 7815…..etc. You use the same potentiometer trick and this
    creates a floating ground circuit so the IC still ‘thinks’ it is regulating
    a lower voltage. These are generally good to about 35 volts DC output max.
    But a great set of videos overall. Say, what brand of O scope would you
    recommend if one does not want spend top dollar ( i’d rather have more
    frequency in exchange! ) thanks

  41. this may sound weird, but I have a similar adjustable regulator that I used
    and it runs along the same base as the LM317. The AMS 1117 ADJ is set up
    the same way, however the formula has nothing to do with it at all what so
    ever. It turns up, it only needs a resistor on the Adj/Grd pin to positive
    and use the ground as normal and I can adjust to any voltage I want. If
    the out pin is connected in any way, the voltage is not regulated (i.e 5
    volts in, 5 volts out if the out pin is connected to anything in any way.)
    I’ve tried extremes for resistance on either R1 or R2, 10 Mohms, 30 Mohms,
    etc…. nothing, even connecting things to purposely short out the OUT from
    the adjust pin. if the out pin is connected it wont bother going through
    anything else it will be what ever the input is. Any ideas?

  42. i am wanting to use a -12v rail and a 12v rail and use the potentiometer to
    adjust between 3.3v and 24v. is the LM317 ok to handle this?

  43. When you are talking about the resulting heat created can we add this value
    to the total consumption of the device we are powering?

  44. Thanks! Works great with a computer power supply. Since a cpu power supply
    has -12v and +12v and voltage is equal to the difference, you can use the
    -12v as the ground instead of a 0v ground and get a variable 24v.

  45. Let’s say that I have a wide-range input voltage (say, 1-volt to 20 volts),
    but I want to use a fixed output voltage of 13.7 volts. Can the LM317T
    accept that much power without smoking it, if I give it a large enough
    heat-sink? I am wanting to build a custom voltage regulator to work for a
    remote DC gen to lead-acid storage cell system, where the charge is
    supplied by a windmill. In theory, this is the same circuit used in older
    cars (voltage regulator preventing overcharge from alternator). Am I
    missing something, or is the voltage regulator on an older automobile not a
    similar circuit?

  48. Can someone explain to me how 50farad*4.7Kohms=0.485+1V=1.485v.
    I’m a bit rusty on my conversions, but I tried converting Farads to ohms*R2
    then convert to volts and did not get what I was displayed in this
    presentation.
    O*F=v, V/F=O…
    200o*3F=600V, 600v/3F=200o/600v=3f

    Thanks

  49. i tried wiring the circuit with the potentiometer… i checked my design
    but i keep burning the potentiometer… why is that?

  59. Thanks, I really should have known that,I saw that later also explained on
    another video. Most videos neglect that part of the equation, they say
    because the difference it makes to the outcome in most instances is
    miniscule.

  61. Hi could you use an adjustable voltage regulator with two 12 volt
    batteries, so you could have adjustable power from 1 volt to 24 volts

  64. Can I use this to charge a battery via solar panel?I mean,if the solar
    panel produces 40 v can i use this setup to charge a 12v battery?

  65. this is by far the best explanation of how to use a LM317. None of the
    other literature i found gave guidelines and explained what happens when
    the Vin and Vout are wildly different. This video was awesome

  67. Let’s say I need 5V at up to 2A of current drawn. How big of a heatsink
    should I use, and what value resistors do I need?

  69. Awesome video!
    What would be the next-best alternative to a linear voltage regulator if
    you were looking for something more efficient?

  70. Im a bit confused after opening up a high end power suply (advanced 19 volt
    6 amp SMPS) and finding loads of N channel mosfets. Googling these
    (“45nq10t” and “k3797”) says the application is dc to dc conversion and
    SMPS’s but what makes them different than Voltage regulators? Could they do
    the job?

  71. I would like to build this device for automotive usage. I would not need it
    to handle very much amperage. Since the range of usage would be from half a
    volt to 12 volts (with little to no amperage), I need to be able to
    determine how much output voltage is being supplied . If I were to place a
    digital volt meter on the output side of this device , would it affect the
    out put voltage ?

  76. Does this circuit adjust amp?
    Because i’ve got a 24v 1.1ah power supply and i want to adjust voltage, but
    i also want to keep amp

  79. Hi Afro, Great video and easy to learn with your clear straightforward
    videos.
    I will be sure to link to your Amazon.com page in the future. Glad to do it
    .!
    Cheers, G.

  80. Lm317 has current limitation i think 1.5 A when i test it with big Rc Car
    7.5v , i put ,12v Lithium useless laptop battery it doesn’t work , i used
    L200.it works .

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