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Author Topic: Raspberry Pi  (Read 27552 times)

Offline bmarkus

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Re: Raspberry Pi
« Reply #30 on: August 06, 2012, 01:16:38 PM »
A phone charger is not a power supply.
Béla
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Offline netnomad

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Re: Raspberry Pi
« Reply #31 on: August 06, 2012, 09:53:40 PM »
i tried two different power supplies...
both are phone chargers:
the first one, a new cheap manufactured chinese product with 700ma i bought on a flee-market for 2 euros and my raspberrypi suffered various malfunctions.
afterwards i bought a new phone-charger with 1000ma for 12 euros and everythings works flawless.
« Last Edit: August 06, 2012, 09:55:44 PM by netnomad »

Offline spence91

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Re: Raspberry Pi
« Reply #32 on: August 07, 2012, 01:36:44 AM »
Official Blackberry chargers are rated 5V 700ma and are *cheap*, plus my work seems to throw one at me every couple of years. That's what I've been using and I've not had any issues - even having 2 devices in both usb ports and using XBMC playing stuff over NFS.

A phone charger is not a power supply.

Supplying power to an electrical load - what else can it be?

Offline bmarkus

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Re: Raspberry Pi
« Reply #33 on: August 07, 2012, 04:40:50 AM »
Supplying power to an electrical load - what else can it be?

A charger is providing power to charge a mobile phone battery where charging is regulated by the phone's electronic and phone itself is powered from the battery having a regulator, filter circuit between battery and and phone. It means, that requirement on stability, noise, etc. is low on charger, it can be a cheap shit.

Powering a cumputer board is a different story, where requirement on voltage stability and noise level on the lines are much higher to protect the board, as well as for example how voltage is changing during on/off can be important for reset circuit, etc. Do not know how Pi, wether there is a voltage stab for example in its power line or line, how reset circuit is built, etc.

Low quality power supply can cause strange system crashes and mulfunctions which would handled as software bug or a hardware failure of the board by most users but it isn't.

So even if you find a phone charger working it is a high risk for your board.
« Last Edit: August 07, 2012, 04:44:40 AM by bmarkus »
Béla
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"Amateur Radio: The First Technology-Based Social Network."

Offline spence91

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Re: Raspberry Pi
« Reply #34 on: August 07, 2012, 05:49:01 AM »
A charger is providing power
Bingo.

http://elinux.org/Rpi_Hardware#Power
According to the online wiki the Pi can take voltages anywhere from 5V to 16V, I think the whole point of deciding on this method of power supply was precisely because many people have mini-usb power supplies at home already because it's become ubiquitous.

I agree with the non-brand phone chargers not being good, I disagree with it being a high risk to your board, most people have issues with too little power not the other way around. It will result in strange failures but will it blow up in your face? I doubt it.

My point is that you can get branded power supplies for very cheap, and most people already have some lying around.

Offline Rich

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Re: Raspberry Pi
« Reply #35 on: August 07, 2012, 07:24:49 AM »
Hi spence91
From the link you provided:
Quote
The board takes fixed 5V input,
Nowhere does it state (that I could find) you can run from 16V. Read this: http://www.raspberrypi.org/archives/260
Also from the link you provided:
Quote
This permits adoption of the micro USB form factor, which, in turn, prevents the user from inadvertently plugging in out-of-range power inputs; that would be dangerous, since the 5V would go straight to HDMI and output USB ports, even though the problem should be mitigated by some protections applied to the input power: The board provides a polarity protection diode, a voltage clamp, and a self-resetting semiconductor fuse.
I took a look at the schematic for the model B, the link for the PDF can be found here: http://www.raspberrypi.org/archives/1090
Here's what I saw for the power supply input:
1. A series connected semiconductor fuse rated for 1.1A at 6V, followed by
2. A shunt connect 5V bi-directional transzorb
3. NO POLARITY PROTECTION DIODE
As you increase the input voltage above 5V, the transorb will begin conducting current and clamp the voltage to the board
at 5V. This excess current will heat up the fuse until you reach about 1.1A, at which point it's resistance suddenly becomes
very high and shuts down the board. Once it cools down, it's resistance once again drops. The purpose of this circuit is to
clamp momentary spikes and surges, not to serve as a mechanism to regulate higher voltages to 5V. If you do actually
apply a solid 16V supply, the transorb will have 5V across it, leaving 11V across the 6V fuse, most likely destroying it.

Offline spence91

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Re: Raspberry Pi
« Reply #36 on: August 07, 2012, 07:44:48 AM »
Rich - my bad, the 16V came from the C6 capacitor that's on the board (I skimmed the article) that aids with DC regulation.

--EDIT--
Also here's a list of Verified power sources - many of them phone chargers.
http://elinux.org/RPi_VerifiedPeripherals#Power_adapters
« Last Edit: August 07, 2012, 07:47:24 AM by spence91 »

Offline Rich

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Re: Raspberry Pi
« Reply #37 on: August 07, 2012, 08:49:15 AM »
Hi spence91
I suspected it was something like that.

@ALL: You want to use a 5 volt 1 amp REGULATED power supply.

Offline cast-fish

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Re: Raspberry Pi
« Reply #38 on: August 14, 2012, 07:44:03 PM »
A phone charger is not a power supply.

You do talk some Rubbish sometimes.

It's like. "did he even read the sentence before posting it?"

Ofcourse a phone charger is a "power supply" because it powers the phone
while charging the phones empty battery.

What school did you go to?

V.

Offline bmarkus

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Re: Raspberry Pi
« Reply #39 on: August 14, 2012, 09:30:45 PM »
A phone charger is not a power supply.

You do talk some Rubbish sometimes.

It's like. "did he even read the sentence before posting it?"

Ofcourse a phone charger is a "power supply" because it powers the phone
while charging the phones empty battery.

What school did you go to?

V.

Thanks. School? M.Sc.E.E in electronics and computer sciences, amateur radio operator with HAREC licence. To be honest I'm tired to discuss hw construction details whith someone who knows nothing about circuits and takes out one sentence without reading deatails.

You can do whatever you want with your toys. Please, let me out of your bussiness.

Thanks.
Béla
Ham Radio callsign: HA5DI

"Amateur Radio: The First Technology-Based Social Network."

Offline Rich

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Re: Raspberry Pi
« Reply #40 on: August 14, 2012, 11:02:18 PM »
Hi cast-fish
Quote
You do talk some Rubbish sometimes.

It's like. "did he even read the sentence before posting it?"
Did you bother to read and understand post #33 written by bmarkus?
Quote
Ofcourse a phone charger is a "power supply" because it powers the phone
while charging the phones empty battery.
Yes, but that does not mean it is a proper power supply for this application. I tried to find some specs for
phone chargers, and none listed whether the output was regulated, what the output tolerance was, or
how much ripple they put out. I did find one that listed its input voltage as 100-240VAC, and its output
voltage as 4.5-9.5VDC, sound like a good power supply to you? Just because a phone can be charged
from a USB port, does not mean its charger is suitable for powering logic circuits.

Offline spence91

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Re: Raspberry Pi
« Reply #41 on: August 16, 2012, 02:38:35 AM »
A phone charger is not a power supply.

You do talk some Rubbish sometimes.

It's like. "did he even read the sentence before posting it?"

Ofcourse a phone charger is a "power supply" because it powers the phone
while charging the phones empty battery.

What school did you go to?

V.

Thanks. School? M.Sc.E.E in electronics and computer sciences, amateur radio operator with HAREC licence. To be honest I'm tired to discuss hw construction details whith someone who knows nothing about circuits and takes out one sentence without reading deatails.

You can do whatever you want with your toys. Please, let me out of your bussiness.

Thanks.

I don't think anyone takes exception to your reasoning or your impressive electronic credentials. I was just calling you up on the blanket statement that was made.
My shaky reply aside, it still remains that the Raspberry Pi foundation endorses a variety of power supplies, with many of them being phone chargers.

What is far more important is of course getting TCL up and running on this board....

Offline netnomad

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Re: Raspberry Pi
« Reply #42 on: August 16, 2012, 03:12:21 AM »
hi friends,

i learnt that if i have problems with my rpi, it's worth to check the power supply.
in my daily work i experience regulary that technical problems are often caused by a poor power supply.
after changing or improving the power supply many problems disappear...

Offline cast-fish

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Re: Raspberry Pi
« Reply #43 on: August 18, 2012, 11:15:15 AM »
Hello

oh mt "phone charge" ppost is  a bit heavy. Sorry. It was just correcting Markus blanket statement
which is incorrect.

his post  "a phone charger is not a power supply"

hie next post

A phone charger is providing power to charge a mobile phone battery where charging is regulated by the phone's electronic and phone itself is powered from the battery having a regulator, filter circuit between battery and and phone. It means, that requirement on stability, noise, etc. is low on charger, it can be a cheap shit.


i hope that clears up why i commented.

In relation to the comment that i have no experience with circuits. (hmmm)

My comments are not Flame Rich and Markus but fact. I stand by what i say as
a roadblock for a wholly 100 percent incorrect comment from BM.

As for the OP....

The Rasberry states that it can work with many "mobile phone chargers"
and it was designed this way. Two hundred thousand Pi's have been sold. Youtube vids show many phone chargers plugging in and powering the Pi. (funnily enough that means the phone charger is a Power Supply).

Rasberry foundation just qoute what electronic specs are needed from a phone charger to allow the charger power the Pi.  They state the required voltage thresholds and current thresholds. Your charger will work right if it is in that catagory.....   If not....then it won't work right.

thanks

Vince.

Offline hiro

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Re: Raspberry Pi
« Reply #44 on: August 18, 2012, 11:28:16 AM »
Stuff breaks, so just try out different chargers, power sources, cables, whatever. Specs don't matter to the Chinese anyway.