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 is a 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 an output voltage as used 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 rectifier 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.

1.5V, 3V, 4.5V, 5V, 6V, 9V adjustable power supply instead of a battery
1.5V, 3V, 4.5V, 5V, 6V, 9V adjustable power supply circuit instead of a battery

Here is the step-by-step process.

  • 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 the output of IC1
  • C3 (10uF)- help to reduce the ripple before is amplified when the output voltage rises up.
  • C4 (0.1uF) reduce the ripple at the 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 the size of the transformer. We should choose the size of 2A. Or size 1A. For those who want to 1A output current only.

How to build this project

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.

pcb-of-lm317-linear-power-supply-regulator-selector-15v3v45v5v6v9v-15a
Figure 2 the PCB of this projects

components-layout-of-lm317-linear-power-supply-regulator-selector-15v3v45v5v6v9v-15a
Figure 3 the components layout and wiring to all parts

 

Others of LM317 voltage selector

Also, you may like these projects below:

My first Variable DC Power Supply, 1.2V to 30V at 1A using LM317
It’s easy and cheap as possible.

0-60V/0-30V DC variable power supply using LM317 & LM337
It is high volt and starts voltage at zero! good job. Read more>>

Best 3A DC power supply, adjustable 1.2V to 20V, 3V-6V-9V-12V
High current for all circuit easy to use. Read more>>

Dual power supply 3V,5V,6V,9V,12,15V with LM317,LM337
There positive and negative voltage output for all circuit easy to use. Read more>>

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shahin

please send mi all project power switching tanks

jozef

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

ivan

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?

Suresh de Fonseka

please send me the correct cct diagram early

chayapon

Hi, ivan

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

chayapon

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

John Sabalboro

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

Nikhil

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

Arman

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

aftab

Thanks very good websit.

chayapol garaipoom

Hi aftab.
Thanks for your feed back.

rod

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

Greg Banks

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… Read more »

duTch

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

MarK

the selector Switch can be replace by Potentiometer?

MarK

The Selector Switch can be replace by a Potentiometer?

Víctor Venegas Flores

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.

Bryan Siyang

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

chayapol garaipoom

Hi Bryan Siyang.
Thanks for your feed back.
Yes we will do it.

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