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LM317 Regulated Power Supply Voltage Select to 1.5V,3V,4.5V,5V,6V,9V 1.5A

Normally begin to learn about electronics power supply from the battery, for example, 9 volts, 1.5 volts, 6 volts etc. But there are disadvantage that when using battery power is discharged. I need to buy a new one. Consume more.

We should the dc power supply have a choice of AC voltage. Which it must provide a output voltage as usage often is 1.5volt, 3 volts, 4.5 volts, 6v, 9v, and the current is about 1 A.

LM317 voltage selector

When we view many circuit ideas, found that the as figure this below (number second the power supply projects in my life) have the best fit. We use a dc voltage regulator number LM317T is the heart of the circuit. Featured, is the constant voltage. Low noise. Almost equal to the voltage of the battery. And short-circuit protection as well.

How it works
When we push power switch (S1) on, the AC-line voltage will pass through a fuse F1 and come to transformer T1 to reduce AC volts down to 12 volts
– Then this current flow through the bridge diode model (D1-D4)-1N4001 to full wave rectifire as DC current and through C1 to filter current to smooth up and has C2 filter ripple signal before into LM317.
-LED to display power on the circuit, with R1(2K) currents to reduce it.

LM317 Regulated Power Supply  Voltage Select to 1.5V,3V,4.5V,5V,6V,9V 1.5A

– The output voltage is determined by rotating a selector switch S2 a level voltage 1.5,3,4.5,5,6,9 volts respectively.
– C5 (10uF) control impedance and reduce a transient at output of IC1

– C3 (10uF)- help to reduce the ripple before is amplified when the output voltage rise up.
– C4 (0.1uF) reduce the ripple at output.
– D5 and D6(1N4001) for protects IC1 from discharging of C3 and C5 respectively. In case the input of IC1 is shorted.
The maximum output current about 1.5A depends on size of the transformer We sould choose size of 2A., Or size 1A for those who want to 1A output current only.

How to build this projects
This project is not used many components so can assemble on the universal PCB board. But can make a PCB as Figure 2. Then, the wiring for circuit wiring and various components can view of the example in Figure 3. What to look out carefully for is the polarity of the electrolytic capacitors and Diodes correctly. Pin of the IC is not an error.

Figure 2 the PCB of this projects

Figure 3 the components layout and wiring to all parts.

We recommend:

This may be liked. but you may like these projects below:

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This Post Has 22 Comments

  1. please send mi all project power switching tanks

  2. Hi, shahin
    thanks for your comment.
    Please find power supply switching on mysite better.
    or get email news member You can always learn new circuits.

  3. Hi,thanks for your comment.your website is beter.
    good lack

  4. Hi, Jozef
    Your welcome.

  5. can u give me a design and a pcb layout of short circuit protected power supply with IC that has a 5v as an output?

  6. Hi, ivan

    Thanks for your feedback,.
    LM317t have short circuit protection.

  7. Hi
    Thanks for your feedback.
    On the circuit is correct.

  8. Sir, its John from the Philippines, What if I want to add 12v and 15v output? What resistor do I need add to work it? Pls. Tell me sir I’d love to do this… Thanks

  9. sir can u please suggest me a 5v dc to 1.5 dc converter?

  10. hi.tanks for god informations.
    can you send mi all project power switching? tanks

  11. Thanks very good websit.

  12. why is it that the 20ohms resistor getting burned, how many watts resistor should i use, thanks

  13. Hi, rod
    D6-1N4002 may be connected to the wrong polarity. or switch direct current to R-20 ohms.

    Please check parts again.
    Good luck.

  14. Hi there. I built a very similar supply for my self many years ago. Suggestion for you, make sure the selector switch is a ” make before break” type. If it is the more common break before make, then as you change the voltage selector from one setting to the next there is a brief moment when it is open circuit. This results in the maximum voltage being present on the output for a moment too. I destroyed a low voltage circuit on my unit ( maximum voltage 18v) switching from 3 to 4.5v You might need to shop around to find a make before break type. But I’m sure the bigger suppliers ( RS or Element 14, etc) will have them. Well worth the little extra money.

  15. So this is interesting- with electronics, I know enough to be dangerous, so ¿¿ if I want to reduce a ~6.0 -7.4 volt input to 3.6 – 4.2 volt usable output, is a ‘completely’ different story yeah?..but not so complicated, how will I achieve this?…and thanks for the output, duTch

  16. the selector Switch can be replace by Potentiometer?

  17. The Selector Switch can be replace by a Potentiometer?

  18. Buen dia.
    Tengo una F.A variable con el LM317, de 1,7 a 27 vc., como sabemos nos da un máximo de 1,5,Amperios;como puedo hacer para agregarle más corriente (hasta 3 Amperios), se que se le puede agregar una resistencia y un transistor de potencia.
    Les estaré muy agradecidos por su respuesta.

  19. Can you post the list of all the parts? Thanks in advance!

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