For those that insist on using switching power supplies
Although this link
http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html
is about the little Line to 5V USB adapters one sees everywhere now days,
it does show how crappy the output looks when one gets a 'bargin'
-pete
And this one to show how safe and well designed they are.<lol>
-=Bryan=-
From: time-nuts time-nuts-bounces@febo.com on behalf of Pete Lancashire pete@petelancashire.com
Sent: October 12, 2016 10:58 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] For those that insist on using switching power supplies
Although this link
http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html
A dozen USB chargers in the lab: Apple is very good, but not quite the besthttp://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html
www.righto.com
When you buy a USB charger, how do you know if you're getting a safe, high-quality charger for your money? You can't tell from the outside...
is about the little Line to 5V USB adapters one sees everywhere now days,
it does show how crappy the output looks when one gets a 'bargin'
-pete
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I've actually got 10 or 12 of those sitting in a box. I got them because of the "grounded" power header. The units I got used the 3-pin header but only had a 2-wire plug. So, something seemed wrong and I opened it up. I noticed the same thing: that the non-soldered ground pin went nowhere. But, I demanded my money back due to the power cord not being as pictured, and went back to my previous supplier of a different power unit. Since it was from China, it wasn't economic to ship them back. It may be that ebay actually paid for the refund, I don't remember. The build quality was pretty poor, and that figures since it had a screw-together clamshell.
Bob
From: Bryan _ <bpl521@outlook.com>
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Wednesday, October 12, 2016 3:42 PM
Subject: Re: [time-nuts] For those that insist on using switching power supplies
And this one to show how safe and well designed they are.<lol>
-=Bryan=-
From: time-nuts time-nuts-bounces@febo.com on behalf of Pete Lancashire pete@petelancashire.com
Sent: October 12, 2016 10:58 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] For those that insist on using switching power supplies
Although this link
http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html
A dozen USB chargers in the lab: Apple is very good, but not quite the besthttp://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html
www.righto.com
When you buy a USB charger, how do you know if you're getting a safe, high-quality charger for your money? You can't tell from the outside...
is about the little Line to 5V USB adapters one sees everywhere now days,
it does show how crappy the output looks when one gets a 'bargin'
-pete
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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www.febo.com
time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ...
and follow the instructions there.
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To be fair here, phone chargers have almost no requirement to be quiet other than conducted and radiated emissions limits.
It's charging a battery.
As a designer of some fairly quiet SMPS systems, this feels like "look how bad a family car this tractor is".
.....but can you listen to the radio in the car ?? Many of these things
will kill other applications like broadband over twisted pair and PLT tv
extension. Never mind killing you!
Alan
G3NYK
----- Original Message -----
From: "Van Horn, David" david.vanhorn@backcountryaccess.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Thursday, October 13, 2016 2:05 PM
Subject: Re: [time-nuts] For those that insist on using switching power
supplies
To be fair here, phone chargers have almost no requirement to be quiet
other than conducted and radiated emissions limits.
It's charging a battery.
As a designer of some fairly quiet SMPS systems, this feels like "look how
bad a family car this tractor is".
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On Oct 13, 2016, at 6:05 AM, Van Horn, David david.vanhorn@backcountryaccess.com wrote:
To be fair here, phone chargers have almost no requirement to be quiet other than conducted and radiated emissions limits.
It’s charging a battery.
Not quite. They power the device in question while they’re charging the battery. Now, I’ll admit that powering a phone is a much lower bar than powering, say, an audio amplifier, but I’d also say that some of the devices on that page were pumping out way more garbage than even any digital system should have to put up with.
As a designer of some fairly quiet SMPS systems, this feels like “look how bad a family car this tractor is".
Well, there’s some of that, but the worst offenders were counterfeit devices that were pumping out unreasonable levels. To your analogy, they were the outer shell of a family car with a the engine from an Edsel installed in it without a muffler or any emissions controls fed from an open bucket of gasoline sitting on the passenger’s seat.
Actually, if they have the "CE" stamp on the product, then they have very
specific radio interference limits that they must test and meet.
It must have been tested, certified, and the certification package
available for inspection.
Whether they actually met it, then pulled the interference supression parts
off the board as a "cost reduction" as is common in no-name computer power
supplies, or whether it never met it to begin with, is for you to
speculate. Some suppliers will explain to you that "CE" means China
Export, not that it meets the consolidated European safety and electrical
rules.
--- Graham
On Thu, Oct 13, 2016 at 5:25 PM, Nick Sayer via time-nuts <
time-nuts@febo.com> wrote:
On Oct 13, 2016, at 6:05 AM, Van Horn, David <david.vanhorn@
backcountryaccess.com> wrote:
To be fair here, phone chargers have almost no requirement to be quiet
other than conducted and radiated emissions limits.
It’s charging a battery.
Not quite. They power the device in question while they’re charging the
battery. Now, I’ll admit that powering a phone is a much lower bar than
powering, say, an audio amplifier, but I’d also say that some of the
devices on that page were pumping out way more garbage than even any
digital system should have to put up with.
As a designer of some fairly quiet SMPS systems, this feels like “look
how bad a family car this tractor is".
Well, there’s some of that, but the worst offenders were counterfeit
devices that were pumping out unreasonable levels. To your analogy, they
were the outer shell of a family car with a the engine from an Edsel
installed in it without a muffler or any emissions controls fed from an
open bucket of gasoline sitting on the passenger’s seat.
time-nuts mailing list -- time-nuts@febo.com
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mailman/listinfo/time-nuts
and follow the instructions there.
Even if they meet the CE or FCC requirements for unintentional
radiators, they can still screw up the short wave bands and more; many
are bad enough that I can see the noise they emit on an oscilloscope
with a shorted probe. At least in the US, there are a lot of cheap
products with switching regulators which cause problems including CFL
and LED lamps and FCC enforcement is poor.
That confusion between the European Economic Area CE and the China
Export CE is just shrewd.
On Thu, 13 Oct 2016 17:57:02 -0500, you wrote:
Actually, if they have the "CE" stamp on the product, then they have very
specific radio interference limits that they must test and meet.
It must have been tested, certified, and the certification package
available for inspection.
Whether they actually met it, then pulled the interference supression parts
off the board as a "cost reduction" as is common in no-name computer power
supplies, or whether it never met it to begin with, is for you to
speculate. Some suppliers will explain to you that "CE" means China
Export, not that it meets the consolidated European safety and electrical
rules.
--- Graham
On Thu, 13 Oct 2016 20:07:41 -0500
David davidwhess@gmail.com wrote:
That confusion between the European Economic Area CE and the China
Export CE is just shrewd.
It's an outright lie
https://en.wikipedia.org/wiki/CE_marking#China_Export
Attila Kinali
--
Malek's Law:
Any simple idea will be worded in the most complicated way.
Benchtop linear power supplies also share in some deceptive marketing
regarding noise. Some have horrible 1/f noise, others are on par to a
tl431, which isn't too bad. Some will have spurious tones 10's of dB above
the Gaussian noise spectrum. Unfortunately most linear power supplies only
spec a total rms noise over 20 Hz - 20 MHz. Whether that's a flat power
spectrum or a handful of tones, is a test it and see senario.
On Wednesday, 12 October 2016, Pete Lancashire pete@petelancashire.com
wrote:
Although this link
http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html
is about the little Line to 5V USB adapters one sees everywhere now days,
it does show how crappy the output looks when one gets a 'bargin'
-pete
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