How
to choose a good USB data and charging cable for your mobile phone
Most of us will have a few USB
data and charging cables for our mobile phone, i.e. one at home, one in office,
one carrying together with our laptop, etc.
Do you encounter the problem of
slow charging, or worst still, unable to charge with the additional USB cable
that you bought? Perhaps you can find the solution after reading this.
First of all, although most of the
USB cables look alike from their external appearance, they might be different
inside the cable, and probably that is the ready why certain USB cable unable
to charge your mobile phone, certain can charge but at a very slow rate,
certain just work as fine as the original USB cable that come with your phone,
and certain even can charge faster than the original cable.
There are 5 wires inside the USB 1
and USB 2 cables, and there are more inside USB 3.0 cable. Since most of the
mobile phones nowadays are using USB 2.0 connector, so USB 3.0 is out of our
topic here.
The 5 wires are:
2x 28 AWG data lines
2x 20-28 AWG power conductors
1x drain wire
and those 5 wires are connected to
the 5 pins in your micro-USB connector.
In fact, there are two kinds of USB
cable: fully-rated and sub-channel. The main difference between them is that
fully-rated cable can be used for typical peripherals operating at the rate of
480 Mbps (high speed) signalling, while the sub-channel one at the rate of 1.5
Mbps (standard speed) signalling. The construction inside the cable fully-rated
and sub-channel cable is different.
As you can see from the diagram
above, the fully-rated USB cable is shielded by braid and aluminium foil.
You can probably see some printed
codes on the good quality USB cable, including something like this:
"28AWG/2C and 24AWG/2C" or "28AWG/1P + 24AWG/2C".
The first code is normally the
specification of the data signal pair, which is normally 28AWG. "2C"
means 2 conductors, and "1P" or "1Pr" means 1 pair.
"2C" and "1P" are basically the same.
The important part is the second
code, which is the specification of the power distribution pair. The minimum
requirement is 28AWG, and the lower the AWG number the better. This is because
lower AWG wire is thinker, and therefore the electrical resistant is lower.
Therefore, charging with a
"28AWG/1P + 28AWG/2C" USB cable is normally slower than a
"28AWG/1P + 24AWG/2C" cable.
Certain USB cable comes with a
ferrite bead at one end, which function is to filter high frequency noise to
improve signal transfer.
As a conclusion, when you buy
additional USB cable to charge your mobile phone, you should look for:
USB 2.0 support
High speed 480 Mbps data transfer
rate
The packaging mentions it is a
"charging" cable and not only a "data" cable
Power conductors of 24AWG/2C or
better (for faster charging speed)
(optionally) the ferrite bead
Remember not to only look for the
information on the packaging of the cable. Sometimes you will find the
specification printed on the cable is different from that mentioned on the
packaging.
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