On 04/11/2022 13:53, Pancho wrote:
> On 04/11/2022 10:52, Robin wrote:
>> On 04/11/2022 08:58, Andy Burns wrote:
>>> Brian Gaff wrote:
>>>
>>>> I think officially 1 amp is the max current of standard USB sockets.
>>>> Even
>>>> that seems to be pushing it a bit in my view.
>>>
>>> What is your view on USB type C sockets allowing up to 5A at 48V ?
>>
>> When I saw the spec now mentioned voltages of up to 50.9V (48V + a 5%
>> tolerance) I was left wondering if there were implications for touch
>> voltages in domestic installations.  E.g. if a USB socket tests just
>> over 50V?
>>
>
> POE Ethernet and POTS Telephones are in the region of 48V. So it is
> nothing new.
>
I got a hefty belt of the back of a PA amplifier generating the odd
100W, which into 8 ohm would a sinusoid of a mere 28V AC.

--
"The most difficult subjects can be explained to the most slow witted
man if he has not formed any idea of them already; but the simplest
thing cannot be made clear to the most intelligent man if he is firmly
persuaded that he knows already, without a shadow of doubt, what is laid
before him."

- Leo Tolstoy

On 04/11/2022 10:52, Robin wrote:
> On 04/11/2022 08:58, Andy Burns wrote:
>> Brian Gaff wrote:
>>
>>> I think officially 1 amp is the max current of standard USB sockets.
>>> Even
>>> that seems to be pushing it a bit in my view.
>>
>> What is your view on USB type C sockets allowing up to 5A at 48V ?
>
> When I saw the spec now mentioned voltages of up to 50.9V (48V + a 5%
> tolerance) I was left wondering if there were implications for touch
> voltages in domestic installations.  E.g. if a USB socket tests just
> over 50V?
>

As far as I'm aware it has to be instructed by the receiving end what
voltage to output. Remove the connection and it probably defaults to 5V

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 04/11/2022 14:30, John Walliker wrote:
> On Friday, 4 November 2022 at 13:53:27 UTC, Pancho wrote:
>> On 04/11/2022 10:52, Robin wrote:
>>> On 04/11/2022 08:58, Andy Burns wrote:
>>>> Brian Gaff wrote:
>>>>
>>>>> I think officially 1 amp is the max current of standard USB sockets.
>>>>> Even
>>>>> that seems to be pushing it a bit in my view.
>>>>
>>>> What is your view on USB type C sockets allowing up to 5A at 48V ?
>>>
>>> When I saw the spec now mentioned voltages of up to 50.9V (48V + a 5%
>>> tolerance) I was left wondering if there were implications for touch
>>> voltages in domestic installations. E.g. if a USB socket tests just
>>> over 50V?
>>>
>> POE Ethernet and POTS Telephones are in the region of 48V. So it is
>> nothing new.
>
> The safety standard for computer and AV equipment is IEC62368.1 which
> has a limit of 60V for "energy source class 1" sources which are considered safe
> to touch.
>
> Here is the definition:
> Under normal operating conditions and abnormal operating conditions, the energy in a
> class 1 source, in contact with a body part, may be detectable, but is not painful nor is it likely
> to cause an injury. For fire, the energy in a class 1 source is not likely to cause ignition.
> Under single fault conditions, a class 1 energy source, under contact with a body part, may
> be painful, but is not likely to cause injury.
> and
> No safeguards are required between a class 1 energy source and an ordinary person (see
> Figure 9). Consequently, a class 1 energy source may be accessible to an ordinary person.
>
> In other words, anything up to 60V (after worst case tolerances have been applied) is fine.
>
> There are special exceptions for telephone ringing signals and loudspeaker outputs
> which allow higher voltages to be touchable that would not otherwise be permitted.
> POE+ and POE++ are rated for voltages up to 57V, so they just fall within the safety
> limits for touchable circuits.
>

Thanks.

With that pointer I see IEC62368.1 Class 1 has a lower limit for AC,
which reminds me I'd completely overlooked the AC/DC issue. I can't
recall if the USB-C spec has anything similar.

--
Robin
reply-to address is (intended to be) valid

"Dave Plowman (News)" <dave@davenoise.co.uk> wrote:
> Some time ago, got this from Lidl. It looks like a small version of an
> outdoors flood light. Came with a desk stand, so can be pointed in most
> directions. Built in battery and wall wart charger. Plenty output as a
> work light. Bounce off the ceiling for general lighting of a room. Lasts
> about 4 hours on a charge.
>
> I'm sure you could buy similar from a cordless drill maker which uses the
> same batteries as the drill, etc. Bound to be better value than something
> made for computers.

I have something like this:
https://www.ebay.co.uk/itm/195370201610

I used it to work in the loft before I installed lighting.

It takes 18650 lithium cells - in my case it shipped with a low capacity
1200mAh battery, but 18650s are widely available either new or from
scrapped laptop batteries.

Charges via USB and also works as a power bank. With two cells you might
get up to about 7000mAh in there. You can swap in other 18650s to make it
go for longer.

There's something to be said for not having everything relying on a single
battery, so you can have light in multiple rooms.

Theo

Robin wrote:

> When I saw the spec now mentioned voltages of up to 50.9V (48V + a 5% tolerance)
> I was left wondering if there were implications for touch voltages in domestic
> installations.  E.g. if a USB socket tests just over 50V?

Given that it's DC, then anything under 120V is classed as ELV, it's only AC
where it becomes LV above 50V

On Friday, 4 November 2022 at 16:09:39 UTC, Robin wrote:
> On 04/11/2022 14:30, John Walliker wrote:
> > On Friday, 4 November 2022 at 13:53:27 UTC, Pancho wrote:
> >> On 04/11/2022 10:52, Robin wrote:
> >>> On 04/11/2022 08:58, Andy Burns wrote:
> >>>> Brian Gaff wrote:
> >>>>
> >>>>> I think officially 1 amp is the max current of standard USB sockets.
> >>>>> Even
> >>>>> that seems to be pushing it a bit in my view.
> >>>>
> >>>> What is your view on USB type C sockets allowing up to 5A at 48V ?
> >>>
> >>> When I saw the spec now mentioned voltages of up to 50.9V (48V + a 5%
> >>> tolerance) I was left wondering if there were implications for touch
> >>> voltages in domestic installations. E.g. if a USB socket tests just
> >>> over 50V?
> >>>
> >> POE Ethernet and POTS Telephones are in the region of 48V. So it is
> >> nothing new.
> >
> > The safety standard for computer and AV equipment is IEC62368.1 which
> > has a limit of 60V for "energy source class 1" sources which are considered safe
> > to touch.
> >
> > Here is the definition:
> > Under normal operating conditions and abnormal operating conditions, the energy in a
> > class 1 source, in contact with a body part, may be detectable, but is not painful nor is it likely
> > to cause an injury. For fire, the energy in a class 1 source is not likely to cause ignition.
> > Under single fault conditions, a class 1 energy source, under contact with a body part, may
> > be painful, but is not likely to cause injury.
> > and
> > No safeguards are required between a class 1 energy source and an ordinary person (see
> > Figure 9). Consequently, a class 1 energy source may be accessible to an ordinary person.
> >
> > In other words, anything up to 60V (after worst case tolerances have been applied) is fine.
> >
> > There are special exceptions for telephone ringing signals and loudspeaker outputs
> > which allow higher voltages to be touchable that would not otherwise be permitted.
> > POE+ and POE++ are rated for voltages up to 57V, so they just fall within the safety
> > limits for touchable circuits.
> >
> Thanks.
>
> With that pointer I see IEC62368.1 Class 1 has a lower limit for AC,
> which reminds me I'd completely overlooked the AC/DC issue. I can't
> recall if the USB-C spec has anything similar.

It does. 48V+/-5% @ 5A maximum, so long as a special cable is used that has
an appropriate identity chip. That means that the maximum possible voltage from
a USB connector is 50.4V.

John

In article <tk3c4p$1s9f3$4@dont-email.me>,
The Natural Philosopher <tnp@invalid.invalid> wrote:
> On 04/11/2022 13:53, Pancho wrote:
> > On 04/11/2022 10:52, Robin wrote:
> >> On 04/11/2022 08:58, Andy Burns wrote:
> >>> Brian Gaff wrote:
> >>>
> >>>> I think officially 1 amp is the max current of standard USB sockets.
> >>>> Even
> >>>> that seems to be pushing it a bit in my view.
> >>>
> >>> What is your view on USB type C sockets allowing up to 5A at 48V ?
> >>
> >> When I saw the spec now mentioned voltages of up to 50.9V (48V + a 5%
> >> tolerance) I was left wondering if there were implications for touch
> >> voltages in domestic installations. E.g. if a USB socket tests just
> >> over 50V?
> >>
> >
> > POE Ethernet and POTS Telephones are in the region of 48V. So it is
> > nothing new.
> >
> I got a hefty belt of the back of a PA amplifier generating the odd
> 100W, which into 8 ohm would a sinusoid of a mere 28V AC.

some PA amps use 100v !

> -

--
from KT24 in Surrey, England - sent from my RISC OS 4té
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 03/11/2022 16:33, Scott wrote:
> On Thu, 3 Nov 2022 16:09:32 +0000, Andy Burns <usenet@andyburns.uk>
> wrote:
>
>> Scott wrote:
>>
>>> There's a Belkin offering 20000 mAh at Argos - that's 20 amp
>>> hours. If I revert to my original premise that the bulb is likely to
>>> be closer to 5 watts, this would require 1 amp (5W/5V) and the lamp
>>> would last for 20 hours. Is this correct? .
>>
>> Not likely, for the reason I mentioned, it could be 20000mAh * (3.7/5.0) minus a
>> few percent for conversion losses, 16000mAh at 5V
>
> Still looking at well over the three hour projected power cuts then?
>>
>> And even less likely for the reason alan_m mentioned, i.e. the 20000mAh is a lie
>> to start with.
>
> Even it it's Belkin :-)
>
> I suppose I could use an inverter instead and a normal lamp, but it
> seems to me that taking mains voltage, transforming it to 12 volts,
> rectifying it to DC, charging a battery, putting it though an inverter
> to return it to 230 volts then powering a lamp would not be an
> efficient process.

I previously tested my 5000mAh power banks and got between 4.8 and 5
hours for an approximately 5w lamp.

I was comparing an expensive Anker power bank, with some cheapo no name
ones. They lit the lamp for the same duration. They recharged in the
same time. The only real difference is that the Anker charges my mobile
phone astonishingly fast, whereas the no names didn't.

At that time, I didn't understand the 3.7v/5v rating convention, so
thought nothing of it. i.e Why they lit the light for longer than expected.

I'll charge a power bank up and test again. The only problem is I don't
know how to accurately measure the wattage of the lamp. How to
accurately measure USB power, The lamp is 5 watt measured via a usb
transformer plugged into a power meter smart plug.

The test starts now 16:40.

On 04/11/2022 17:04, John Walliker wrote:
> On Friday, 4 November 2022 at 16:09:39 UTC, Robin wrote:
>> On 04/11/2022 14:30, John Walliker wrote:
>>> On Friday, 4 November 2022 at 13:53:27 UTC, Pancho wrote:
>>>> On 04/11/2022 10:52, Robin wrote:
>>>>> On 04/11/2022 08:58, Andy Burns wrote:
>>>>>> Brian Gaff wrote:
>>>>>>
>>>>>>> I think officially 1 amp is the max current of standard USB sockets.
>>>>>>> Even
>>>>>>> that seems to be pushing it a bit in my view.
>>>>>>
>>>>>> What is your view on USB type C sockets allowing up to 5A at 48V ?
>>>>>
>>>>> When I saw the spec now mentioned voltages of up to 50.9V (48V + a 5%
>>>>> tolerance) I was left wondering if there were implications for touch
>>>>> voltages in domestic installations. E.g. if a USB socket tests just
>>>>> over 50V?
>>>>>
>>>> POE Ethernet and POTS Telephones are in the region of 48V. So it is
>>>> nothing new.
>>>
>>> The safety standard for computer and AV equipment is IEC62368.1 which
>>> has a limit of 60V for "energy source class 1" sources which are considered safe
>>> to touch.
>>>
>>> Here is the definition:
>>> Under normal operating conditions and abnormal operating conditions, the energy in a
>>> class 1 source, in contact with a body part, may be detectable, but is not painful nor is it likely
>>> to cause an injury. For fire, the energy in a class 1 source is not likely to cause ignition.
>>> Under single fault conditions, a class 1 energy source, under contact with a body part, may
>>> be painful, but is not likely to cause injury.
>>> and
>>> No safeguards are required between a class 1 energy source and an ordinary person (see
>>> Figure 9). Consequently, a class 1 energy source may be accessible to an ordinary person.
>>>
>>> In other words, anything up to 60V (after worst case tolerances have been applied) is fine.
>>>
>>> There are special exceptions for telephone ringing signals and loudspeaker outputs
>>> which allow higher voltages to be touchable that would not otherwise be permitted.
>>> POE+ and POE++ are rated for voltages up to 57V, so they just fall within the safety
>>> limits for touchable circuits.
>>>
>> Thanks.
>>
>> With that pointer I see IEC62368.1 Class 1 has a lower limit for AC,
>> which reminds me I'd completely overlooked the AC/DC issue. I can't
>> recall if the USB-C spec has anything similar.
>
> It does. 48V+/-5% @ 5A maximum, so long as a special cable is used that has
> an appropriate identity chip. That means that the maximum possible voltage from
> a USB connector is 50.4V.
>

Sorry, I meant anything that similarly restricts the 48V to DC. (I had a
quick search of the spec without finding anything about AC power. I
also couldn't find anything that explicitly forbids it but that may be
'cos it's considered apparent to anyone with 2 brain cells to rub together.)

--
Robin
reply-to address is (intended to be) valid

On 04/11/2022 16:56, Andy Burns wrote:
> Robin wrote:
>
>> When I saw the spec now mentioned voltages of up to 50.9V (48V + a 5%
>> tolerance) I was left wondering if there were implications for touch
>> voltages in domestic installations.  E.g. if a USB socket tests just
>> over 50V?
>
> Given that it's DC, then anything under 120V is classed as ELV, it's
> only AC where it becomes LV above 50V
>

Yes, thanks, another "D'Oh!" from me.
--
Robin
reply-to address is (intended to be) valid

On Friday, 4 November 2022 at 17:39:10 UTC, Robin wrote:
> On 04/11/2022 16:56, Andy Burns wrote:
> > Robin wrote:
> >
> >> When I saw the spec now mentioned voltages of up to 50.9V (48V + a 5%
> >> tolerance) I was left wondering if there were implications for touch
> >> voltages in domestic installations. E.g. if a USB socket tests just
> >> over 50V?
> >
> > Given that it's DC, then anything under 120V is classed as ELV, it's
> > only AC where it becomes LV above 50V
> >
> Yes, thanks, another "D'Oh!" from me.

Table 4 in the standard gives the following ES1 limits:
dc 60V
ac up to 1kHz 30Vrms 42.4Vpk
ac 1kHz to 100kHz 30Vrms + 0.4 f
ac above 100kHz 70Vrms

for ES2 the limits are:
dc 120V
ac up to 1kHz 50Vrms 70.7 pk
ac 1kHz to 100kHz 50Vrms + 0.9 f
ac above 100kHz 140Vrms

For ordinary persons, the following shall not be accessible:
– bare parts at ES2, except for the pins of connectors. However, such pins shall not be
accessible under normal operating conditions by the blunt probe of Figure V..3

For audio signals, table E.1 applies:
When classifying audio signals (see Table E.1), the equipment shall be operated to deliver
maximum non-clipped output power into its rated load impedance. The load is removed
and the electrical energy source class is determined from the resulting open-circuit output
voltage.
For ordinary (uninstructed) persons
ES1: 0-70Vrms No safeguard necessary
ES2: 71-120Vrms Insulated terminals marked with ISO7000 exclamation mark in triangle
or instructional safeguard for uninsulated parts of terminals and bare wiring indicating that
touching uninsulated terminals or wiring may result in an unpleasant sensation.

At even higher voltages (ES3) there are more stringent insulation requirements.

Just to be clear about what devices this standard applies to:
This part of IEC 62368 is applicable to the safety of electrical and electronic equipment within
the field of audio, video, information and communication technology, and business and office
machines with a rated voltage not exceeding 600 V.

John

On 04/11/2022 17:23, Pancho wrote:
> On 03/11/2022 16:33, Scott wrote:
>> On Thu, 3 Nov 2022 16:09:32 +0000, Andy Burns <usenet@andyburns.uk>
>> wrote:
>>
>>> Scott wrote:
>>>
>>>> There's a Belkin offering 20000 mAh at Argos - that's 20 amp
>>>> hours.  If I revert to my original premise that the bulb is likely to
>>>> be closer to 5 watts, this would require 1 amp (5W/5V) and the lamp
>>>> would last for 20 hours.  Is this correct? .
>>>
>>> Not likely, for the reason I mentioned, it could be 20000mAh *
>>> (3.7/5.0) minus a
>>> few percent for conversion losses, 16000mAh at 5V
>>
>> Still looking at well over the three hour projected power cuts then?
>>>
>>> And even less likely for the reason alan_m mentioned, i.e. the
>>> 20000mAh is a lie
>>> to start with.
>>
>> Even it it's Belkin :-)
>>
>> I suppose I could use an inverter instead and a normal lamp, but it
>> seems to me that taking mains voltage, transforming it to 12 volts,
>> rectifying it to DC, charging a battery, putting it though an inverter
>> to return it to 230 volts then powering a lamp would not be an
>> efficient process.
>
> I previously tested my 5000mAh power banks and got between 4.8 and 5
> hours for an approximately 5w lamp.
>
> I was comparing an expensive Anker power bank, with some cheapo no name
> ones. They lit the lamp for the same duration. They recharged in the
> same time. The only real difference is that the Anker charges my mobile
> phone astonishingly fast, whereas the no names didn't.
>
> At that time, I didn't understand the 3.7v/5v rating convention, so
> thought nothing of it. i.e Why they lit the light for longer than expected.
>
> I'll charge a power bank up and test again. The only problem is I don't
> know how to accurately measure the wattage of the lamp. How to
> accurately measure USB power, The lamp is 5 watt measured via a usb
> transformer plugged into a power meter smart plug.
>
> The test starts now 16:40.
>
Test stop 21:18 so 4.63 hours. Still longer than I would expect.

On 04/11/2022 17:08, charles wrote:
> In article <tk3c4p$1s9f3$4@dont-email.me>,
> The Natural Philosopher <tnp@invalid.invalid> wrote:
>> On 04/11/2022 13:53, Pancho wrote:
>>> On 04/11/2022 10:52, Robin wrote:
>>>> On 04/11/2022 08:58, Andy Burns wrote:
>>>>> Brian Gaff wrote:
>>>>>
>>>>>> I think officially 1 amp is the max current of standard USB sockets.
>>>>>> Even
>>>>>> that seems to be pushing it a bit in my view.
>>>>>
>>>>> What is your view on USB type C sockets allowing up to 5A at 48V ?
>>>>
>>>> When I saw the spec now mentioned voltages of up to 50.9V (48V + a 5%
>>>> tolerance) I was left wondering if there were implications for touch
>>>> voltages in domestic installations. E.g. if a USB socket tests just
>>>> over 50V?
>>>>
>>>
>>> POE Ethernet and POTS Telephones are in the region of 48V. So it is
>>> nothing new.
>>>
>> I got a hefty belt of the back of a PA amplifier generating the odd
>> 100W, which into 8 ohm would a sinusoid of a mere 28V AC.
>
> some PA amps use 100v !
>
>> -
>
That amp used ±50V DC for the rails which eqautes to 28V AC.

Its unusual to go much above that as it represents the limits of
reasonably priced semiconductor power devices.

In bridge mode that could be 400W into 4ohm. Not many speakers will
handle that.

Even a 4x12 unit or a 2x15 bass cab cant take much more than that.

--
“The urge to save humanity is almost always only a false face for the
urge to rule it.”
– H. L. Mencken

On 03/11/2022 16:33, Scott wrote:
> I suppose I could use an inverter instead and a normal lamp, but it
> seems to me that taking mains voltage, transforming it to 12 volts,
> rectifying it to DC, charging a battery, putting it though an inverter
> to return it to 230 volts then powering a lamp would not be an
> efficient process.

That would be silly, just make use of a car 12v LED directly.

On 03/11/2022 15:10, Scott wrote:
> Could someone check my homework please :-)
>
> I am thinking about a USB powered lamp in the event of future power
> cuts - linked to a powerbank. I believe the typical output from a
> powerbank is 2 amps at 5 volts. I assume an LED bulb will consume no
> more than 5 watts. If 2 amps at 5 volts is 10 watts (V x I ), this
> should be more than adequate to power the lamp.
>
> Am I missing something?

A lot of car starter power banks come with an inbuilt led torch. However
one thing to consider is some of the higher power LED torches can get
rather warm in prolonged use.

How much light do you you require? I have a 2W LED up-lighter in one of
my rooms and although possibly not enough light to easily read a book by
it illuminates all of my room and everything in it can be seen. I have a
emergency light wired in my landing and the small green charging LED
(probably less than 1/8 Watt) provides enough illumination to dimly
light my way to the bathroom

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On Thursday, 3 November 2022 at 15:10:43 UTC, Scott wrote:
> Could someone check my homework please :-)
>
> I am thinking about a USB powered lamp in the event of future power
> cuts - linked to a powerbank. I believe the typical output from a
> powerbank is 2 amps at 5 volts. I assume an LED bulb will consume no
> more than 5 watts. If 2 amps at 5 volts is 10 watts (V x I ), this
> should be more than adequate to power the lamp.
>
> Am I missing something?

Facts :) Find out what the ratings actually are.

Your options:
1. Battery (eg 3.7v), ballast, LED die
2. battery bank outputting 5v, ballast, LED
3. 12v battery, 12v LED bulb
4. Battery, mains inverter, mains LED bulb
5. Tiny model stirling engine, pmdc generator, transformer ballast, moore's tube.

On 11/4/2022 11:35 AM, Dave Plowman (News) wrote:
> In article <jsi582Fa75dU1@mid.individual.net>,
> Andy Burns <usenet@andyburns.uk> wrote:
>> Also the powerbank may quote the capacity as e.g. 20,000mAh (why not 20Ah?)
>
> Because it looks better to those who don't understand such things?

In some of the adverts I've seen, they also tell you
how many times it will charge an iPad or a laptop
before running dry. And typically it only recharges
a major consumer item about twice, before running out.

Now, something this size, would keep a light on
for a few days. If you could find one manufactured
locally, maybe the markup would not be so high.

https://curiouscampervans.com/products/sok-206-lithium-battery?variant=42464602194178

Paul

In article <tk5s6l$2gcu7$2@dont-email.me>,
The Natural Philosopher <tnp@invalid.invalid> wrote:
> >> I got a hefty belt of the back of a PA amplifier generating the odd
> >> 100W, which into 8 ohm would a sinusoid of a mere 28V AC.
> >
> > some PA amps use 100v !
> >
> >> -
> >
> That amp used ±50V DC for the rails which eqautes to 28V AC.

> Its unusual to go much above that as it represents the limits of
> reasonably priced semiconductor power devices.

Look at a Quad 50. One of the first 100v line solid state amps. Used an
output transformer.

--
*Beware - animal lover - brakes for pussy*

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

On Fri, 04 Nov 2022 15:35:41 +0000 (GMT), "Dave Plowman (News)"
<dave@davenoise.co.uk> wrote:

>In article <jsi582Fa75dU1@mid.individual.net>,
> Andy Burns <usenet@andyburns.uk> wrote:
>> Also the powerbank may quote the capacity as e.g. 20,000mAh (why not 20Ah?)
>
>Because it looks better to those who don't understand such things?

Same principle as - I read at the weekend a US campaign leaflet made
the claim that the other candidate was found with 1000 mg of some drug
in his possession?

On Sun, 6 Nov 2022 09:57:01 +0000, alan_m <junk@admac.myzen.co.uk>
wrote:
[snip]
>How much light do you you require? I have a 2W LED up-lighter in one of
>my rooms and although possibly not enough light to easily read a book by
>it illuminates all of my room and everything in it can be seen. I have a
>emergency light wired in my landing and the small green charging LED
>(probably less than 1/8 Watt) provides enough illumination to dimly
>light my way to the bathroom

Stop the press - results now available.

I got the lamp on Saturday. It comes with a USB plug (no charger). I
attached it to a 10,000 mAh power bank. It runs for about 8 hours on
full power. It's a desk lamp, so perfectly adequate for reading in
bed or elsewhere during a blackout.

Two observations: (1) It interferes badly with my DAB alarm radio. As
the latter will not be working during a power cut, this does not
matter; (2) The LED bulb flickers every minute or so when switched
off. I don't know if this is incompatibility with my choice of power
supply or just a feature of LEDs. Again, this is not a problem as I
can just unplug it when not in use.

On Thursday, 3 November 2022 at 20:39:57 UTC, Scott wrote:
>
> but a very large battery). I am now looking for a desk type lamp so I
> can read in bed if early nights become mandated.
The best thing for that is a head torch.
Bill

On Tue, 15 Nov 2022 07:10:59 +1100, wrights...@f2s.com
<wrightsaerials@f2s.com> wrote:

> On Thursday, 3 November 2022 at 20:39:57 UTC, Scott wrote:
>>
>> but a very large battery). I am now looking for a desk type lamp so I
>> can read in bed if early nights become mandated.

> The best thing for that is a head torch.

Best thing for that is a kindle paperwhite.

On 14/11/2022 12:54, Scott wrote:
> Stop the press - results now available.
>
> I got the lamp on Saturday. It comes with a USB plug (no charger). I
> attached it to a 10,000 mAh power bank. It runs for about 8 hours on
> full power. It's a desk lamp, so perfectly adequate for reading in
> bed or elsewhere during a blackout.
>
> Two observations: (1) It interferes badly with my DAB alarm radio. As
> the latter will not be working during a power cut, this does not
> matter; (2) The LED bulb flickers every minute or so when switched
> off. I don't know if this is incompatibility with my choice of power
> supply or just a feature of LEDs. Again, this is not a problem as I
> can just unplug it when not in use.

If it interferes badly with your DAB radio that suggests its putting out
a lot of RFI (Radio frequency interference). There are standards for RFI
in the UK, and I'll be surprised if one putting out enough to kill DAB
passes. I wonder if it passes all the safety standards?

(you reminded me BTW to make sure my car jump starter pack is charged.
It has a built-in torch which might be handy!)

Andy

On Sun, 20 Nov 2022 20:56:41 +0000, Vir Campestris
<vir.campestris@invalid.invalid> wrote:

>On 14/11/2022 12:54, Scott wrote:
>> Stop the press - results now available.
>>
>> I got the lamp on Saturday. It comes with a USB plug (no charger). I
>> attached it to a 10,000 mAh power bank. It runs for about 8 hours on
>> full power. It's a desk lamp, so perfectly adequate for reading in
>> bed or elsewhere during a blackout.
>>
>> Two observations: (1) It interferes badly with my DAB alarm radio. As
>> the latter will not be working during a power cut, this does not
>> matter; (2) The LED bulb flickers every minute or so when switched
>> off. I don't know if this is incompatibility with my choice of power
>> supply or just a feature of LEDs. Again, this is not a problem as I
>> can just unplug it when not in use.
>
>If it interferes badly with your DAB radio that suggests its putting out
>a lot of RFI (Radio frequency interference). There are standards for RFI
>in the UK, and I'll be surprised if one putting out enough to kill DAB
>passes. I wonder if it passes all the safety standards?

I think it was because the radio was about two inches away. Is it not
also possible that the radio is is to blame for not passing RFI
rejection standards?
>
>(you reminded me BTW to make sure my car jump starter pack is charged.
>It has a built-in torch which might be handy!)

Always happy to assist :-)