ebay, weird bench supply - Page 1
Forum section: electronics / beginners

author: 6PTsocket
author_rank: Regular Contributor
timestamp: June 04, 2019, 02:38:10 pm
content: I am looking for a linear bench supply and I came across this one that said "linear" but reading further it said " PWM voltage stabilization. I emailed the seller to find our which it was and got this answer:"Thanks for your letter and your interests in our product.The item uses PWM switching voltage stabilizer and MOS linear adjustment mode."Is this double talk for a switching power supply by a seller repeating the blurb that came from China with the PS or is it some hybrid technology I am unaware of? Are they talking about the DC output that is fed back to the PWM controller to regulate the supply? Thanks.I have since found another candidate Mastech/Voltq that is definitely linear, less than a mv of noise and 4 digit neters that resolve to 1ma. Nice for general use but I am curious about the first ad.Sent from my SM-G900V using Tapatalk

author: JackJones
author_rank: Regular Contributor
timestamp: June 04, 2019, 02:53:33 pm
content: What's the manufacturer and model?Maybe they are using switching supply for preregulation to a linear one or something?

author: 6PTsocket
author_rank: Regular Contributor
timestamp: June 04, 2019, 03:47:43 pm
content: Quote from: JackJones on June 04, 2019, 02:53:33 pmBrand: YeacomUSA, Model: YES2990. Output: 0-30volts, 10A. Price: around 56 bucks.I don't even see a name on the front panel. It is clearly a Chinese generic. The brand is just the California importer. They did invite me to call for more info. It HAS to be a switcher at that price.Sent from my SM-G900V using Tapatalk

author: 6PTsocket
author_rank: Regular Contributor
timestamp: June 04, 2019, 03:48:50 pm
content: Quote from: 6PTsocket on June 04, 2019, 03:47:43 pmOops! Typo. That is YescomUSASent from my SM-G900V using Tapatalk

author: 6PTsocket
author_rank: Regular Contributor
timestamp: June 04, 2019, 03:55:15 pm
content: I just googled the brand and they also import dance (stripper) poles and tents. Glad I didn't bother to call. LOL!! Can you imagine trying to get tech support?Sent from my SM-G900V using Tapatalk

author: JackJones
author_rank: Regular Contributor
timestamp: June 04, 2019, 04:18:22 pm
content: Definitely a rebranded one, I found dozens of different brands for the exact same looking model. It's pretty common to see them rebranded even with the better quality ones.The specs seem to be 50mV of ripple, given they promise 10A in such a compact looking size I bet it's purely a switchmode supply.I did find a picture of one in a review:https://ae01.alicdn.com/kf/UTB8j_i6H8ahduJk43Jaq6zM8FXav.jpgDoesn't look linear to me!

author: ArthurDent
author_rank: Super Contributor
timestamp: June 04, 2019, 04:41:33 pm
content: As mentioned, some power supplies use a switching mode preregulator to increase efficiency then a linear final regulator so there is a low voltage drop across the linear stage for low heat dissipation and you get the added advantage of lower noise and probably better regulation.

author: strawberry
author_rank: Super Contributor
timestamp: June 04, 2019, 10:01:17 pm
content: Quote from: JackJones on June 04, 2019, 04:18:22 pmToo large capacitance at output terminals.