Re: Pi power

From	Tim Streater <timstreater@greenbee.net>
Newsgroups	comp.sys.raspberry-pi
Subject	Re: Pi power
Date	2021-01-06 10:44 +0000
Message-ID	<i5lil0Foj7cU4@mid.individual.net> (permalink)
References	<i5k91cFoj7cU2@mid.individual.net> <i5kab6FrpbpU2@mid.individual.net> <rt40p2$fj2$1@posie.signal11.org.uk> <rt43h5$93k$1@dont-email.me>

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On 06 Jan 2021 at 10:31:01 GMT, Martin Gregorie <martin@mydomain.invalid>
wrote:

> On Wed, 06 Jan 2021 09:44:02 +0000, Mike wrote:
> 
>>  In article <i5kab6FrpbpU2@mid.individual.net>,
>>  Andy Burns  <usenet@andyburns.uk> wrote:
>>> Tim Streater wrote:
>>  
>>>>  The Pi carried on being powered.
>>  
>>> Unless a 4B is different to any other rPi, they never turn off, they
>>> just halt.
>>  
>>  But, from the original post, which you snipped :-
>>  
>>>  A bit later I shut it down, **and then turned off the Pi power
>>>  supply.**
>>>  The Pi carried on being powered.
>>  
>>  Are you saying the Pi 4B is a stealth free-energy device? ;)
> 
> Its not. This just shows that, if there are common positive and ground 
> rails on the Pi's PCB that are connected to ALL sockets capable of 
> accepting a connection from an externally powered peripheral device, 
> which AFAIK is the case for all Pi models, then a Pi will remain active 
> as long as external device with a power source providing enough current 
> to keep the RPi alive is connected to it.
> 
> It also means that you can destroy a Pi by connecting it to anything 
> which requires more than 5v to operate and that has its positive and 
> ground rails connected to the plug it uses to talk to the Pi.

OK. So what device is providing the power to the HDMI cables, and why? In my
setup I have a Dell display connected via its DVI (?) socket and an adapter to
a small HDMI switcher that can route the display either to my Mac Mini or to
the Pi.

I did notice that, after disconnecting the HDMI from the Pi, and reconnecting
it (all this with the Pi's power adapter unplugged from the mains), the Pi did
not power up again. So whatever is on  teh HDMI is not a strong power source.

-- 
Tim

Thread

Pi power Tim Streater <timstreater@greenbee.net> - 2021-01-05 22:54 +0000
  Re: Pi power Andy Burns <usenet@andyburns.uk> - 2021-01-05 23:16 +0000
    Re: Pi power "Mayayana" <mayayana@invalid.nospam> - 2021-01-05 19:59 -0500
      Re: Pi power A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-06 07:31 +0000
        Re: Pi power "Mayayana" <mayayana@invalid.nospam> - 2021-01-06 08:18 -0500
        Re: Pi power jornws200602@xs4all.nl (Oscar) - 2021-01-06 14:02 +0000
    Re: Pi power mjb@signal11.invalid (Mike) - 2021-01-06 09:44 +0000
      Re: Pi power Martin Gregorie <martin@mydomain.invalid> - 2021-01-06 10:31 +0000
        Re: Pi power Tim Streater <timstreater@greenbee.net> - 2021-01-06 10:44 +0000
          Re: Pi power Joe <joe@jretrading.com> - 2021-01-06 11:03 +0000
      Re: Pi power Tim Streater <timstreater@greenbee.net> - 2021-01-06 10:32 +0000
        Re: Pi power Andy Burns <usenet@andyburns.uk> - 2021-01-06 10:57 +0000
          Re: Pi power TimS <timstreater@greenbee.net> - 2021-01-06 11:44 +0000
            Re: Pi power Andy Burns <usenet@andyburns.uk> - 2021-01-06 12:10 +0000
              Re: Pi power TimS <timstreater@greenbee.net> - 2021-01-06 13:25 +0000
                Re: Pi power Andy Burns <usenet@andyburns.uk> - 2021-01-06 14:41 +0000
                Re: Pi power TimS <timstreater@greenbee.net> - 2021-01-06 15:17 +0000
                Re: Pi power Martin Gregorie <martin@mydomain.invalid> - 2021-01-06 16:05 +0000
                Re: Pi power TimS <timstreater@greenbee.net> - 2021-01-06 16:14 +0000
        Re: Pi power A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-06 12:02 +0000
      Re: Pi power Andy Burns <usenet@andyburns.uk> - 2021-01-06 10:55 +0000
        Re: Pi power Chris Green <cl@isbd.net> - 2021-01-06 11:19 +0000
          Re: Pi power Axel Berger <Spam@Berger-Odenthal.De> - 2021-01-06 13:13 +0100
            Re: Pi power Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-06 12:47 +0000
              Re: Pi power Joe <joe@jretrading.com> - 2021-01-06 20:20 +0000
                Re: Pi power druck <news@druck.org.uk> - 2021-01-06 20:43 +0000
              Re: Pi power Eli the Bearded <*@eli.users.panix.com> - 2021-01-06 23:08 +0000
                Re: Pi power Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-07 07:40 +0000
                Re: Pi power Axel Berger <Spam@Berger-Odenthal.De> - 2021-01-07 09:08 +0100
                Re: Pi power John Aldridge <jpsa@cantab.net> - 2021-01-07 09:20 +0000
                Re: Pi power The Natural Philosopher <tnp@invalid.invalid> - 2021-01-07 08:16 +0000
                Re: Pi power druck <news@druck.org.uk> - 2021-01-07 09:53 +0000
                Re: Pi power Martin Gregorie <martin@mydomain.invalid> - 2021-01-07 12:40 +0000
                Re: Pi power Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2021-01-07 19:29 +0000
                Re: Pi power David Higton <dave@davehigton.me.uk> - 2021-01-07 21:05 +0000
          Re: Pi power Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-06 12:39 +0000
            Re: Pi power Chris Green <cl@isbd.net> - 2021-01-06 17:04 +0000
              Re: Pi power Theo <theom+news@chiark.greenend.org.uk> - 2021-01-06 18:02 +0000
          Re: Pi power Theo <theom+news@chiark.greenend.org.uk> - 2021-01-06 16:41 +0000
            Re: Pi power Martin Gregorie <martin@mydomain.invalid> - 2021-01-06 17:04 +0000
              Re: Pi power druck <news@druck.org.uk> - 2021-01-06 18:50 +0000
                Re: Pi power Martin Gregorie <martin@mydomain.invalid> - 2021-01-06 20:39 +0000
            Re: Pi power TimS <timstreater@greenbee.net> - 2021-01-06 18:58 +0000
  Re: Pi power Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2021-01-08 22:33 -0500
    Re: Pi power Anssi Saari <as@sci.fi> - 2021-01-09 12:03 +0200

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