HI, I would like to build voltage regulated source that should give 5 no's of 2v,2.5v and 3v .I am using(5 no's) lm317 with 3 resistance trimmer each connected with 3 turn switch.Idea is when turning switches i should get 2v,2.5,3v respectively.4 no's of lm317 isolated and 5th one is grounded.i got values for first 4 and not for 5/Pls help

 

Post your circuit or pictures of your wiring.

 

@hameed123 , Welcome to AAC.

Are you trying to duplicate this circuit from the datasheet?


Except using switches instead of the transistors?

John

 

 

thanks for the reply....this is my ckt ...output is not stable after pot adjusted

 

thanks for the reply....this is my ckt ...output is not stable after pot adjusted

The image is too small and blurry to see the detail.
Post a larger image and not in .jpeg format.

 

Pls look out this

MY CIRCUIT

PDF

 

hi 123,
Your diagram is so big I can see my house.
This clip showing only two sections of your diagram, which shows 5 identical circuits, is easier to follow.
E

 

YES ,,,,,4 LM317 ARE CONNECTED WITH NO GROUND AND THE 5 TH ONE IS GROUNDED...HEADER 3 IS THE 3 WAY TURN SWITCH TO GET 2,2.5,AND 3V RESPECTIVELY.......I NEED TO TAKE OUTPUT WHICH IS FROM HEADER 6(6 TH PIN IS GROUNDED TO 5 TH LM 317

I SHOULD GET 5 DIFFERENTIAL OUTPUT FROM HEADER PIN 6()

IF ALL THE SWITCH IS IN 1ST STATE THE OUTPUT SHOULD BE 2V
2 ND STATE -----2.5V
3 RD STATE -----3V

 

Ouch- all capital letters is not nice... please don't.

 

Ouch- all capital letters is not nice... please don't.

okkk

 

4 LM317 ARE CONNECTED WITH NO GROUND

What do you mean by "no ground"?
All LM317's need to have at least one of their pot resistors going to ground.

If you show the complete schematic, we can better know what the circuit is doing.

 

Hello,

@crutschow , the full schematic is in the PDF's in post #7.

Bertus

 

the full schematic is in the PDF's in post #7.

I meant a full schematic showing how the pots are connected through their connectors.

 

3 rd pin of header 3 will go to next lm317 positive terminal of cap 1uF

negative terminal of 1uF,0.1uF,10uF,and 27 ohms all interconnected to next lm 317 s positive terminal of 1uF

 

Sorry, I don't understand your description.
Please post a schematic.

 

Hello,

I would check your connections.
Some spots are connected and some not ( I have circled them).
Also the pots shouls have a connection to a reference ( I have drawn some ):



Bertus

 

You must have at least one resistor to gnd, like R2 in the app circuit.
And try to keep the wires to the switches and pots as short as you can.
One problem with switched voltage setting is usually the output will go to the max it can as you switch from one setting to another as the switches go open.
Why do you want to use switches in stead of a pot?

And I see you are using a 10K resistor from output to adjust. Make it 240R or 220R and see if that helps. Then you can get rid of the 27R on each output.

 

thanks all......sorry for the late reply.I will try Mr.bertus and Mr.Dendad and come back again