3v step down from 12v

[bidrohini]

hi
all my projcets are run on 12v adaptors leds and mini motors
i want to add 3v leds to my display
is this the board i can use to boost up safely?

https://www.aliexpress.com/item/1005006379415643.html?spm=a2g0o.productlist.main.3.416e4db1BDfCxj&algo_pvid=09940bf2-eff9-44d3-9f06-ff273c4c0494&algo_exp_id=09940bf2-eff9-44d3-9f06-ff273c4c0494-1&pdp_npi=4%40dis%21USD%213.16%211.04%21%21%2122.65%217.43%21%40211b801717083301048224328e4ec9%2112000036962762116%21sea%21IL%21133542592%21&curPageLogUid=T5ehcTemX3Fc&utparam-url=scene%3Asearch%7Cquery_from%3A

The one in your link is a boost/step up converter. You do not need this. If you want to step down from 12V to 3V, you need a buck converter. That is also called step down converter. You can use an LM2596. You can design a module with LM2596 like this. With the LM2596 Adjustable DC-DC Converter, you can regulate input voltages between 4V DC - 35V DC in the range of 1.23V DC - 30 VDC. You can adjust the output voltage according to your desire with the trimpot on it. This module, which is very useful with its small dimensions, contains LM2596 regulating integration. The circuit can carry current up to 3A DC. A small 30 mV deviation margin provides a great advantage over other DC-DC converters.

-Buck Converter LM2596 - Share Project - PCBWay

BUCK CONVERTER LM2596 Voltage Reducer Adjustable Power Module “With the LM2596 Adjustable DC-DC Converter, you can regulate input voltages between 4V DC - 35V DC in the range of 1.23V DC - 30 VDC. You...

www.pcbway.com

 

[Bluejets]

The one in your link is a boost/step up converter. You do not need this. If you want to step down from 12V to 3V, you need a buck converter.

Already covered in #19.....

 

[Crafts4Me]

I must be doing something wrong. it doesnt flicker and gets much too hot I got a burn

 

[Martaine2005]

Please provide more information.
What is getting hot?.
As already stated, have you got a buck converter?. Step down.
If things are getting hot, you’ve probably exceeded the current limit of your device.
Please explain your issue and give the information on the device you are using and the things you have connected to it.

 

[Delta Prime]

it doesnt flicker and gets much too hot I got a burn

That's unacceptable! Please,stop what you are doing and please answer the questions.

 

[bertus]

Hello,

Did you follow the instructions in post #19 given by @Bluejets ?
You will need to cut a trace on top and solder two points for the given voltage together.

Bertus

 

[Crafts4Me]

hi
i am a crafter not an electrician.

I didnt solder yet, I used wires to test if it will work
I used the lamp:

https://www.aliexpress.com/item/1005006434966191.html?spm=a2g0o.order_list.order_list_main.65.21ef1802TqzZbJ

step down:

https://www.aliexpress.com/item/1005005995617482.html?spm=a2g0o.order_list.order_list_main.70.21ef1802TqzZbJ

after connecting the wires the lamp doesnt flicker and it gets too hot in a few seconds.

after reading complaints people said its 2.5 not 3v
would that make a difference
do I maybe need a resistor?

 

[bertus]

Hello,

Can you measure the output voltage of the down converter?
When you did not make any changes, the potmeter on the board sets the output voltage.

Bertus

 

[Crafts4Me]

i am sorry i dont have a tool to measure voltage
is it an important tool to own for "playing" with electricity?

 

[Harald Kapp]

It is. I dare say its is essential. In your case: how are you going to adjust your step-down regulators without a way of knowing the output voltage?
A good starting point is a so called multimeter: measures voltage, current, resistance and sometimes more. Cheap ones can be had for a few bucks only, sometimes even in your local hardware store.
Better ones are more expensive, but also more reliable and precise.

For the occasional user - that's you - an inexpensive multimeter is imho the best choice.

 

[Crafts4Me]

will order one
so i guess till then i cannot address the problem, correct?

 

[Harald Kapp]

so i guess till then i cannot address the problem, correct?

Not really.

If you are willing to possibly sacrifice a lamp or two: set the potentiometer on the step-down module to the extreme left position (counterclockwise). This should minimize the output voltage:

Connect one of your LED lights to the output. Connect the 12 V source to the input. the lamp should be off. Slowly adjust the potentiometer clockwise until the lamp turns on and flickers without getting hot.

Unfortunately the ad for the step-down module doesn't tell us a lot abot the module. There is a slight chance that the potentiometer works the other way: counterclockwise = higher voltage. Unexpected but possible. In this case your lamp will immediately get hot and possibly burn out. Then you should reverse teh directions I gave above and try again, possibly with a new lamp.

btw: the lamp you used for your tests so far may be damaged by overvoltage.

 

[Crafts4Me]

i will try
can it make a fire or just burn out the flame bulb. i can sacrifice a bulb. i am afraid of fire

 

[Harald Kapp]

can it make a fire

Always a possibility, but when you put the module and the lamp on a fire-prood surface (even an old baking tray will do) not much can happen as the energies involved are small. You risked as much with the test you described in post #27. Be rady to disconnect the 12 V source immediately and if youre really afraid have a fire extiguisher ready.
It's up to you how much you invest in safety.

 

[Crafts4Me]

perfect will use a tray and also a dc plug with on-off switch so i can disconnect immediately worst will be a short
i will report after testing

 

[bertus]

Hello,

You could buy a decent multimeter at amazon:

https://www.amazon.com/gp/aw/d/B0B57PFFYX/ref=dp_ob_neva_mobile

Bertus

 

[Crafts4Me]

would this one be ok?

https://www.amazon.com/Multimeter-Non-Contact-Electrical-Auto-Ranging-Continuity/dp/B0CR7P4BFY/ref=sr_1_21?crid=1CL2BDEOHG5WF&dib=eyJ2IjoiMSJ9.7-f6L0H0-

 

[Harald Kapp]

Yes.

 

[Crafts4Me]

i purchased locally in an electronics hardware store. i will follow the instructions or watch a tutorial how to use and measure
thanks for the advise

 

[Crafts4Me]

hi
please help me
which setting do i use to test th output voltage on the step down?