Wednesday, 4 May 2011

How to make a variable power supply using LM317

 



        LM317 - 3 Terminal Positive Adjustable Regulator
    • Output range             -        1.2V - 37V 
    • Current capacity       -         1.5A 
    • Vout                           -        1.25 (1 + R2 / R1) + I adj * R2.                   ( I adj * R2 is neglected ) 
    • Package                     -        TO220 
    • Line regulation          -         0.01% 
    • Load regulation         -         0.1%                           
             *reference voltage - 1.25V


             Circuit


      *C2 - 10uf - 470uf 50V is better.( Electrolytic capacitor )
      *C1 - 0.1uf - Ceramic capacitor.
      *R1 must be 240R.( 0.125W)
      *R2 linear potentiometer.
      *Diode 1N4007 can be connected across Vout and Vin. 
        ( A of 1N4007 to Vout and K to Vin. )
       









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      2 comments:

      1. Nguyễn Tuấn9 November 2012 at 07:14

        thank!

        ReplyDelete
      2. Anonymous20 February 2013 at 07:56

        im just wondering, and want to learn , can you please explain why is that in R2 the higher value of resistor in ohms produce more increase in voltage in adjust pin of LM317. thank you so much

        ReplyDelete

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