For the life of me I cannot seem to get this simple circuit to work... I have created similar circuits in the past without any issues. I simply want to bring in 13v and output to an adjustable 2-12 volts. Seems simple right.

I have tried multiple LM317s, multiple resistors, multiple pots, multiple breadboards... no matter what I do the volts out will only adjust between 10-12volts. Any help would be appreciated. I initially had the setup with the capacitors, but removed them to trouble shoot my issue.

My layout with LM317, 240 resistor, 5k pot...

Reference...

 

what happens if you short out the pot to ground?

 

what happens if you short out the pot to ground?

The pot is connected to the ground (-) already... can you explain what you mean. Sorry I am just a hobbyist

 

I think I see a 750 ohm on the board. The regulator would like that to be 120 or at most 240 ohms.

 

He means what is the output V when you add a wire right across your pot.

 

Th pins of LM317 shows in the circuit was wrong, if count the pins of LM317 from left are 1,2,3 then the 1--adj, 2-- Vout, 3-- Vin, so you have to recheck the circuit, the pins should be like this way, Vin=3, Adj=1, Vout=2, please check this.

 

Th pins of LM317 shows in the circuit was wrong, if count the pins of LM317 from left are 1,2,3 then the 1--adj, 2-- Vout, 3-- Vin, so you have to recheck the circuit, the pins should be like this way, Vin=3, Adj=1, Vout=2, please check this.

Yes I noticed half of the diagrams online don't show the correct pin numbers... if you check the photo, I got the right pins connected to the rights components... I think anyways.

 

Yes I noticed half of the diagrams online don't show the correct pin numbers... if you check the photo, I got the right pins connected to the rights components... I think anyways.

I don't think the wiring on breadboard is right, please recheck it.

 

Is the front of lm317 facing the camera?
Another problem is that the LM317 needs 3V drop voltage between Vin and Vout, so when you want a 12V output then you should input 15V.

 

Is the front of lm317 facing the camera?
Another problem is that the LM317 needs 3V drop voltage between Vin and Vout, so when you want a 12V output then you should input 15V.

Yes that is the front of the LM317... even if I set the Vin to 15V then I get a range of 13V-14V. I have spent all day on this simple circuit. I have rechecked. The photo shows a different resistor, but even with a 240 I get the same results. I don't know how many diagrams I have downloaded, and printed out for reference.

This is driving me crazy haha. I have built power regulators before.

 

I don't think the wiring on breadboard is right, please recheck it.

Rechecked... this time I added the caps... still, with about 13Vin.... I get a range of about 11V-12V

 

If you have an ohm meter then remove the trimmer pot and check the resistance between the terminals that you are using.
As someone else mentioned, you stated that the fixed resistor that you are using is 240 Ω, but the picture shows a 560 Ω.
That would throw off the LM317 resistor formula if you were using 240.

 

Please check R2, R3(pot) using multimeter.
Do you have another LM317?

 

Rechecked... this time I added the caps... still, with about 13Vin.... I get a range of about 11V-12V

Al, I hate to ask, but have you considered that your LM317 may be defective? Do you have others that you can try?
I once burned one and it was nearly a dead short.

 

If you have an ohm meter then remove the trimmer pot and check the resistance between the terminals that you are using.
As someone else mentioned, you stated that the fixed resistor that you are using is 240 Ω, but the picture shows a 560 Ω.
That would throw off the LM317 resistor formula if you were using 240.

In the new photo I have the 240 installed... removed the pot and checked the resistance between the two pot connectors... I got -7.5 on the 20k voltmeter setting. I am guessing that is 7500? Not sure if the negative symbol means anything.

 

Please check R2, R3(pot) using multimeter.
Do you have another LM317?

R2 = 240
R3 Pot = 5000
I have retried another LM317... same results.

 

Al said "In the new photo I have the 240 installed... removed the pot and checked the resistance between the two pot connectors... I got -7.5 on the 20k voltmeter setting. I am guessing that is 7500? Not sure if the negative symbol means anything"

You can't check resistance on the voltage setting. What brand and model of meter do you have? I might be able to help you with the dial settings
so that you can measure resistance.

 

R2 = 240
R3 Pot = 5000
I have retried another LM317... same results.

Is it possible the LM317 is not a real LM317?

 

Replace the pot with a 1kΩ resistor and see what you get.

Also, your photo labels indicate that you are running this between +12V and -12V. Are you?

 

Replace the pot with a 1kΩ resistor and see what you get.

Also, your photo labels indicate that you are running this between +12V and -12V. Are you?

I just thought the means of -12V is GND.