Hardware Reference
In-Depth Information
The Apple unit seemed to work fairly well when HDMI graphics were
not
being
utilized (using serial console, SSH, or VNC). However, I found that when HDMI was
used and the GPU had work to do (move a window across the desktop, for example),
the system would tend to seize up. This clearly indicates that the adapter does not fully
deliver or regulate well enough.
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Be very careful of counterfeit apple chargers/adapters. the raspberry pi Foun-
dation has seen returned units damaged by these. For a video and further information, see
Caution
E-book Adapters
Some people have reported good success using e-book power adapters. I have also
successfully used a 2 A Kobo charger.
Best Power Source
While it is possible to buy USB power adapters at low prices, it is wiser to spend more on
a high-quality unit. It is not worth trashing your Raspberry Pi or experiencing random
failures for the sake of saving a few dollars.
If you lack an oscilloscope, you won't be able to check how clean or dirty your supply
current is. A better power adapter is cheaper than an oscilloscope. A shaky/noisy power
supply can lead to all kinds of obscure and intermittent problems.
A good place to start is to simply Google “recommended power supply Raspberry Pi.”
Do your research and include your USB peripherals in the power budget. Remember that
wireless USB adapters consume a lot of current—up to 500 mA.
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a random Internet survey reveals a range of 330 ma to 480 ma for wireless USB
adapter current consumption.
Note
Voltage Test
If you have a DMM or other suitable voltmeter, it is worthwhile to perform a test after
powering up the Pi. This is probably the very first thing you should do, if you are
experiencing problems.
Follow these steps to perform a voltage test:
1.
Plug the Raspberry Pi's micro-USB port into the power
adapter's USB port.
2.
Plug in the power adapter.
