DC Power Supply that says 12-24V - Page 1
Forum section: electronics / beginners

author: DW1961
author_rank: Frequent Contributor
timestamp: October 09, 2020, 05:31:30 pm
content: I was thinking about getting one of these units for other than critical use, such as testing LED strips, and so on. However, for instance, my laptop (not that I would use a cheap unit on my laptop) says the power supply in 19V. So, how does a 12-24 V PSU regulate its voltage to make sure it isn't over volting? For instance, if I want to test a 12V LED strip, and the PSU says 12-24V?

author: bob91343
author_rank: Super Contributor
timestamp: October 09, 2020, 05:34:02 pm
content: It's unclear what you are asking. I know of no power supply that puts out 12-24 Volts. It's one or the other, or something else, but it can't be two voltages at once.

author: SmokedComponent
author_rank: Regular Contributor
timestamp: October 09, 2020, 05:52:16 pm
content: It could mean it has an adjustment trimpot.But you never know with the cheapies...

author: DW1961
author_rank: Frequent Contributor
timestamp: October 09, 2020, 06:17:13 pm
content: It just says 12-24V. See, that's what I was thinking that it's either one voltage or another, unless it can automatically switch or something. The output on teh supply says 19.5V, so I think the description is misleading.If you plug that into a 12V device, isn't it going to over volt it? Or would the devices circuitry keep it from doing that, and just take the volts it needs?

author: radiolistener
author_rank: Super Contributor
timestamp: October 09, 2020, 06:43:03 pm
content: It looks like unregulated power supply. It can produce different voltage and your equipment will be burned out if you connect it to such PSU.I recommend to buy KORAD KA3005D. It allows to setup output voltage from 0V to 30V and current from 0A to 5A precisely, also it has OCP and OVP protection.

author: tooki
author_rank: Super Contributor
timestamp: October 09, 2020, 07:36:16 pm
content: Quote from: DW1961 on October 09, 2020, 05:31:30 pmPlease post a link to or photo of the power supply in question.Quote from: bob91343 on October 09, 2020, 05:34:02 pmUnless it’s a constant-current power supply, which are common for LED lighting. Those adjust the voltage to maintain a constant current.

author: DW1961
author_rank: Frequent Contributor
timestamp: October 09, 2020, 07:59:14 pm
content: Here it is:https://www.amazon.com/dp/B07X8PV2JZ

author: james_s
author_rank: Super Contributor
timestamp: October 09, 2020, 08:04:27 pm
content: Maybe the interchangeable tips contain a resistor or other component used tell the PSU which tip is installed and thus which voltage to select? I'm not a fan of these "universal" solutions but it could be handy to have one around.

author: Twoflower
author_rank: Frequent Contributor
timestamp: October 09, 2020, 08:18:11 pm
content: The product description at Amazon is optimized to generate as many hits as possible. If the product description tries to cover the whole data sheet usually I don't trust the description at all.Here's the manufacturers page of the supply:http://www.tenwei.com/index.php?c=product&a=detail&id=40(Data sheet; site is in Chinese but PDF is english:https://pan.baidu.com/s/1S89Ys5zwFEh6hwqD1oBdLQ)● Dimension: 105*60*26mm● Input Voltage: AC 100–240V● Output Voltage: 19V/3.42A● Output Power: 65W● AC Input Cable 1000mm● DC Power Output Cable 1000mm● Storage Temperature -40 to 40° C • Operating Temperature 0 to 40° C● Built-In Circuit Protection Overvoltage, under voltage, over temperatureSo nothing 12-24V. It's fixed 19V

author: james_s
author_rank: Super Contributor
timestamp: October 09, 2020, 10:06:58 pm
content: Well that's annoying. Sometimes Amazon really drops the ball in how items get listed. If there's too much noise in the search I sometimes end up just shopping somewhere else.

author: TimFox
author_rank: Super Contributor
timestamp: October 09, 2020, 10:55:35 pm
content: Was that Amazon listing for the device itself, or did Amazon sort the universe of devices into bins, and this one fell into "12 to 24" with its 19 V rating?Elsewhere, I complained about several DC power supplies listed on eBay as "250 V, 1 A", which was actually the rating of the line fuse on the nameplate.

author: radiolistener
author_rank: Super Contributor
timestamp: October 10, 2020, 12:18:58 am
content: Quote from: DW1961 on October 09, 2020, 07:59:14 pmaccording to product description it has 19.5V12-24V is probably possible customized version which needed to ask seller to sell customized item

author: DW1961
author_rank: Frequent Contributor
timestamp: October 10, 2020, 05:22:36 am
content: It's just a 19V 65 watt PSU. I hope when people plug this into their devices, the device itself has it's own voltage regulation.Ohhhh gawwwwd. It never ends.

author: tooki
author_rank: Super Contributor
timestamp: October 10, 2020, 02:37:47 pm
content: They’re just banking on the fact that pretty much all modern high-tech gadgets use lots of internal regulation. (Consider that in a laptop, outside of the power supply/battery charging infrastructure, the only component thatdoesn’tuse 5V or less is the LCD backlight.)