Hi, I'm a complete newbie in electronics so please bear with me. I came across this diagram online. I tried to build the circuit and made some slight changes on the values of some of the components. The changes made are the following:

• Transformer || 15V to 12V - 1 Amp
• Diode 1 & 2 || 1N4001 to 1N5004
• C2 || 10uf to 0.1uf
• All capacitors are change into 50V rating
• POT || 5k ohms to 1k ohms

I tried to simulate it on multisim before testing the actual circuit and changed the power rating of the POT into 1/8 and it turned out okay with an output of 1.25V to 11.7V. Although when I tried the circuit on actual, the POT smoked almost immediately when I turned the circuit on.

Please help me on this, I want to learn and determine the problem. I'll try again after I get some suggestions and solutions.

P.S. I checked the connections on my PCB and nothing are connected wrong. I think the problem lies around the regulator or the POT...

 

Welcome to AAC!

Diode 1 & 2 || 1N4001 to 1N5004

Overkill.

C2 || 10uf to 0.1uf

Why? 10uF would be better in most cases.

All capacitors are change into 50V rating

Overkill

POT || 5k ohms to 1k ohms

OK.

Although when I tried the circuit on actual, the POT smoked almost immediately when I turned the circuit on.

Something was wired wrong. Only 10mA goes through the pot.

 

It is not wired as a Potentiometer, but a variable resistance mode.

 

What is the wattage rating of the pot you are using.

I once smoked one of those tiny little 1/8 watt multi turn pots in a configuration like that.

 

Could your LM317 be a fake?

 

What is the wattage rating of the pot you are using.

I once smoked one of those tiny little 1/8 watt multi turn pots in a configuration like that.

it's also a 1/8 rated POT

 

Could your LM317 be a fake?

Honestly, I don't know but it's also possible. If you could tell me, how do I know if mine was fake all along or not? I'll check it tomorrow.

 

it's also a 1/8 rated POT

\( \large P = I^2R = 10mA^2*1k=0.1W \)

Try again with a 1k 1/4W resistor instead of the pot.

Honestly, I don't know but it's also possible. If you could tell me, how do I know if mine was fake all along or not? I'll check it tomorrow.

Where did you get the LM317 from?

You can wire your circuit with the adjust terminal connected to ground. The output should be around 1.25V.