Using a 3.5mm jack to power a LED wiring help

Thread Starter

HazenAL

Joined Sep 1, 2020
13
Hello everyone,
Im designing a PCB and I want to include a 3.5mm jack to power the LED by. Here's Datasheet of the connector I want to use. My question is how do I wire it up? The reason why I'm using a 3.5mm jack is because It can be removed if the wire gets caught on something. If you guys know of any better alternatives please let me know.
How do I determine the + and - ?
 

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MisterBill2

Joined Jan 23, 2018
7,021
There is one serious concern, which is that the 3.5 mm connectors are frequently short-circuited during insertion and removal. That may cause problems with the power source. A much better choice is the barrel style connector that is used for many power connections all over. It does not short circuit during insertion or removal, and they can carry more current without heating and voltage drop problems. They are also a lot stronger and much less subject to braking off.
Also, the 3.5mm connectors are mostly used for audio applications and so there is a risk of damaging some audio device that gets connected accidentally.
 

Thread Starter

HazenAL

Joined Sep 1, 2020
13
hi H,
Welcome to AAC.
I would wire it this way.
Green 0V,, Red +V

How much current do the LED's draw from the supply.?
I assume its a low voltage DC supply.?

View attachment 217655
E
Thank you Eric,
The LED driver will be receiving 5V from a power bank. And the LED itself needs will take 430mA and around 3.3V (I don't remember the exact number).
I'm thinking of using a barrel type connector as per the other comment.
 

Thread Starter

HazenAL

Joined Sep 1, 2020
13
There is one serious concern, which is that the 3.5 mm connectors are frequently short-circuited during insertion and removal. That may cause problems with the power source. A much better choice is the barrel style connector that is used for many power connections all over. It does not short circuit during insertion or removal, and they can carry more current without heating and voltage drop problems. They are also a lot stronger and much less subject to braking off.
Also, the 3.5mm connectors are mostly used for audio applications and so there is a risk of damaging some audio device that gets connected accidentally.
Noted. I'm switching over to a barrel style, I don't know what I was thinking haha- one of those tunnel vision moments. However, I would like your input on this: This LED setup will be mounted to glasses. It'll be powered with 430mA, around 3V, and travel from the waist to the forehead. What's the smallest wire gauge can I get away with? I'm also thinking of having the insulation be nylon braided.
 

MisterBill2

Joined Jan 23, 2018
7,021
The majority of wal-wart supplies us what looks like #24 gage wire. However, given that this will be an application with a lot of flexing, I recommend using #22 wire because of better durabiity. If you can find some of the "super-flex" wire that has lots of really fine wire that would be even better, because it is intended for high-flexing applications.
 

SamR

Joined Mar 19, 2019
2,586
Also, being low voltage DC, the wire size gets derated if over 15 feet for 12V. Would be even more so for 3.3V. Don't think I have ever seen deratings tables for 3.3V? Most wall warts only have ~3' connector cable so probably don't get derated.
 

Thread Starter

HazenAL

Joined Sep 1, 2020
13
Also, being low voltage DC, the wire size gets derated if over 15 feet for 12V. Would be even more so for 3.3V. Don't think I have ever seen deratings tables for 3.3V? Most wall warts only have ~3' connector cable so probably don't get derated.
Thank you Sam. The wire will travel from the waist line to the head. So around 2'.
 

Thread Starter

HazenAL

Joined Sep 1, 2020
13
From where are you determining the amperage (430 mA)?

3.3V X 0.430A (430 mA) = 1.419W (watts). What type of LED are you using?
[edited incorrect math symbol]
Hey Tony,
This is a Nichia LED. The current is set by the sense resistor I'm using the with the driver.
 

Tonyr1084

Joined Sep 24, 2015
5,070
I'm still wondering from where you get your numbers. In order to answer your question properly we need a data sheet. Do you have a link to a data sheet?
 
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