5V fan behind Jack DC - Page 1
Forum section: electronics / beginners

author: Kantilo
author_rank: Contributor
timestamp: May 22, 2021, 11:11:41 pm
content: Hello, I got a guide that uses a 12V fan in a project, and I would have liked to adapt it to a 5V fan, can you confirm that my way of doing things is ok?Project instructions for the 12V :QuoteSo I was going to take a female DC Jack, and a fan extension that I cut in half to recover male and female, I cut the fan connector and connect the fan to the extension on the male side, a schema :On the DC Jack connector there is a long and short pin, the short pin = the pin inside?Should be ok, right?Thanks

author: ledtester
author_rank: Super Contributor
timestamp: May 22, 2021, 11:55:28 pm
content: Well, a DC jack has connectors for the center pin and the barrel. Which is positive versus negative depends entirely on the DC adapter you plug into it.Most DC adapters are center positive, but this is not universal. Check the polarity symbol on the adapter itself, e.g.:As for the connections on the DC jack... I would verify all of your assumptions with a multimeter. Usually the tab towards the rear of the jack is connected to the center pin, but you should double check this for your jack.

author: ledtester
author_rank: Super Contributor
timestamp: May 23, 2021, 02:20:48 am
content: What USB adapter are you talking about? I don't see that mentioned in your original post.

author: ledtester
author_rank: Super Contributor
timestamp: May 23, 2021, 02:43:29 am
content: Yeah, in this case plugging the cable into an active USB socket and measuring the voltage between the center and barrel is a good way to check the polarity.Be careful not to short the leads while making the measurement. USB port are supposed to be short-circuited protected, but still it's not a good idea to short it out.

author: Kantilo
author_rank: Contributor
timestamp: May 23, 2021, 03:14:26 am
content: Thank you for taking the time to help me, it is not good for the power supply I imagine, and not the multimeter, precisely I had a cut while using my soldering iron in USB PD when the tin was touching the tip (it doesn't do it all the time and it didn't do it for me again) do you have any idea where it could come from? Hope it didn't damage the soldering iron

author: ledtester
author_rank: Super Contributor
timestamp: May 23, 2021, 03:28:44 am
content: Here's what I understand - perhaps you can clarify...1. you have a soldering iron powered by a USB 3.0 Power Delivery adapter2. while you were using it the tip of the soldering iron touched (something)3. that created a shortWere you soldering on a powered circuit?Is there some device that's not working now?

author: Kantilo
author_rank: Contributor
timestamp: May 23, 2021, 04:06:34 am
content: That's exactly it, I have a video to illustrate the words, sorry I'm not Englishhttps://files.catbox.moe/c1adnq.mp4So it's not a powered circuitSo far nothing has been damaged but I'm afraid it will damage my soldering iron, I don't know if this is the case

author: ledtester
author_rank: Super Contributor
timestamp: May 23, 2021, 04:24:35 am
content: In the video what is the wire connected to?

author: Kantilo
author_rank: Contributor
timestamp: May 23, 2021, 04:27:00 am
content: It's a coil of tin that I hold in my hand

author: ledtester
author_rank: Super Contributor
timestamp: May 23, 2021, 05:50:01 am
content: Try a different power supply. I would try a transformer based wallwart. The Pinecil has a DC jack you can use for power.The problem could be:- the USB PD power supply- the control electronics in the Pinecil- the temperature sensor in the tipDo you have another tip you can test with?

author: Kantilo
author_rank: Contributor
timestamp: May 23, 2021, 05:52:31 am
content: I have a second pinecil I have exactly the same problem with it, and on both using the DC Jack port I don't have the problem

author: ledtester
author_rank: Super Contributor
timestamp: May 23, 2021, 06:26:13 am
content: That suggests that the USB PD power supply is the problem.Or, it could be the USB-C port on the Pinecil.I'd try testing with another USB PD adapter.I'd also try testing the USB PD adapter itself with other devices -- especially ones that can put the PD adapter into the higher voltages -- 15V and 20V.

author: BeBuLamar
author_rank: Super Contributor
timestamp: May 23, 2021, 01:47:49 pm
content: If you connect it with the wrong polarity the fan would run backward. No harm done.

author: janoc
author_rank: Super Contributor
timestamp: May 23, 2021, 02:03:30 pm
content: Quote from: BeBuLamar on May 23, 2021, 01:47:49 pmUuuh, LOL, no. Fans like these use BLDC motors driven by a piece of electronics in the hub.If you connect it in reverse, you will most likely destroy it, it will certainly not run backwards!

author: janoc
author_rank: Super Contributor
timestamp: May 24, 2021, 03:08:36 pm
content: Pinecil specs:QuoteOn barrel jack it is meant to work with up to 24V.So no, it won't damage it, at least as far as voltage is concerned.

author: janoc
author_rank: Super Contributor
timestamp: May 25, 2021, 05:14:26 pm
content: Quote from: Kantilo on May 24, 2021, 03:17:46 pmDoes not matter. If you are using USB PD supply, the device will negotiate only as much voltage as it can handle/needs. So unless your Pinecil is broken/buggy and asks for more than it can handle or your USB supply is not standard compliant you don't need to worry about it.

author: Kantilo
author_rank: Contributor
timestamp: June 21, 2021, 10:12:00 pm
content: Thanks, and what about the cuts they damage the soldering iron?

author: janoc
author_rank: Super Contributor
timestamp: June 22, 2021, 11:09:44 am
content: Quote from: Kantilo on June 21, 2021, 10:12:00 pmYou mean the power was interrupted? It will most likely not damage it but that is not normal either. You will want to fix that. Either the power supply is not sufficient for the current draw of the iron or there is some dodgy contact somewhere.

author: tooki
author_rank: Super Contributor
timestamp: June 22, 2021, 04:00:37 pm
content: Quote from: BeBuLamar on May 23, 2021, 01:47:49 pmAbsolutely, positively not true.Quoted for emphasis:Quote from: janoc on May 23, 2021, 02:03:30 pm