Project # 06   

1.2 ~ 24V @1A,  Regulated DC Power Supply Using LM317
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This simple low-cost DC power supply circuit provide very stable  DC voltage (adjustable) from 1.2V to 24V. The use of LM317T regulator IC simplifies the circuit by reducing the number of required external components. The total parts count is less than 10

The maximum output current is 1A

You may use it to power your electronic projects that requires stable DC supply.

 

 

FEATURES :
OUTPUT VOLTAGE RANGE: 1.2 TO 24V

 
0.1% LINE AND LOAD REGULATION
BUILT-IN PROTECTIONS:  CURRENT LIMITING, THERMAL SHUTDOWN AND SOA CONTROL

Equation for calculation of output voltage:
Vout =1.25 x ( 1+ VR1/(R3+R4) )
where
R3 =470Ω,  R4= 56Ω &  VR1 adjustable from 0 ~ 10KΩ

Eg.:
VR1=0
Ω when it's fully counter-clockwise,  Output voltage =  1.25x(1+0/(470+56) = 1.25V

VR1=10K Ω when it's fully  clockwise,  Output voltage =  1.25x(1+10,000/(470+56) = 1.25x(1+19) = 25V
 


     

PARTS LIST
(the following components will be included in the package unless otherwise stated)

IC1 :   LM317T  3-terminal adjustable linear voltage regulator IC
 Datasheet  
 
LED1 -- 3mm or 5mm LED 

 
D1, D2
  -- 1N540x  (X=2,...,8) rectifier diodes

Resistor  : ( 1/4W or 1/6W)

  • R1 -- Jumper (bare wire)
  • R3 -- 470Ω
  • R4 -- 56Ω
  • R5 -- 3.3K


Potentiometer  :  (B) 10K (linear taper) 
     (output voltage adjustment)

Capacitors :

  • C1  -- either 2200 uF,  3300 uF or 4700uF
    Electrolytic capacitor. 35V min
     
  • C2  --  100 uF  25V (min) Electrolytic capacitor

Miscellaneous items :

 
2-contact screw terminal block -- x 1 pc.
 3-contact screw terminal block -- x 1 pc.

TO-220 Heat Sink (for IC1)  --- x 1 pc.

Printed Circuit Board (included)
Etched & drilled with component side printing 
-----  x 1 pc. 

Power transformer required :  (  HT-24E1-5)
(NOT INCLUDED)
Primary :  ~230V,   Secondary : 24V-0-24V  @1A