Hardware Reference
In-Depth Information
Again, take into account that not all USB hubs work with (Raspbian) Linux. The
kernel needs to cooperate with connected USB hubs, so software support is critical. The
following web page lists known working USB hubs:
Power Adapters
This section pertains mostly to the Model B because the Model A is easily supported by a
USB 2 port. We'll first look at an unsuitable source of power and consider the factors for
finding suitable units.
An Unsuitable Supply
The example shown in Figure
2-4
was purchased on eBay for $1.18 with free shipping
(see the upcoming warning about fakes). For this reason, it was tempting to use it.
Figure 2-4.
Model A1265 Apple adapter
This is an adapter/charger with the following ratings:
•
Model
: A1265
•
Input
: 100-240 VAC
•
Output
: 5 V, 1 A
When plugged in, the Raspberry Pi's power LED immediately lights up, which is a
good sign for an adapter (vs. a charger). A fast rise time on the power leads to successful
power-on resets. When the voltage was measured, the reading was +4.88 V on the +5 V
supply. While not ideal, it is within the range of acceptable voltages. (The voltage must be
between 4.75 and 5.25 V.)
