What are the differences between USB 2, USB 3, and USB 4?
|Version||Transfer Speed (bit)||Maximum Power||Maximum Voltage||Maximum Current||Supported Devices|
|USB 2.0||480 Mbps||2.5 W||5 V||500 mA||
|USB 3.1 GEN 1||5 Gbps||4.5 W||5 V||900 mA||-|
|USB 3.1 GEN 2||10 Gbps||4.5 W||5 V||900 mA||
|USB 3.2 Gen 2x2||20 Gbps||7.5 W||5 V||1500 mA||-|
|USB 4||40 Gbps||100 W||20 V||5000 A||
Apple Device Supported Wattage
|32/36 W||iPad、Macbook Air|
|65 W 以上||Macbook Air、Macbook Pro|
Is the higher wattage of the power adapter, the faster the charging speed?
It depends on the
maximum wattage supported by your charging device. Typically, devices have a limit on the maximum wattage they can accept to prevent damage.
|Charger wattage||Supported wattage by the charging device||Wattage during charging|
|10 W||20 W||
|20 W||20 W||
|30 W||20 W||
|100 W||20 W||
The highest charging wattage supported by iPhones
The highest charging wattage supported by the iPhone is
20W. So, even if you use a charging cable that’s rated for
more than 20W, the iPhone will only charge at a
maximum of 20W, and it won’t charge any faster.
The charging speed of a dual-port USB is faster?
The packaging usually indicates the
total power output, which is typically
divided in half for each port. So, the wattage for a single port is halved, rather than added together. It’s important to check the specifications on the packaging for confirmation.
|Maximum Supported Wattage||Output Ports 1||Output Ports 2|
|30 w||15 w||15 w|
|100 w||50 w||50 w|
How to check the wattage provided by the power adapter?
Look for the power adapter specifications indicating the
highest 'voltage and
current, then simply
multiply them together.
How to choose a power adapter?
Consider the maximum wattage supported by your frequently used devices. Chargers with
higher wattage can provide power to devices that require lower wattage.
1. Look at the
maximum supported wattage of your devices.
If your devices
don't support a higher wattage, buying a power adapter with a higher wattage rating would be pointless and a waste of money.
2. Portability and price
The portability and price depend on whether you need to carry it with you regularly for charging. Typically, the
higher the wattage, the heavier the power adapter, and the more expensive it tends to be.
How to choose a charging cable?
1. Supported Wattage
The higher the wattage, the faster the charging speed, and the higher the price.
Also, consider the devices you frequently need to charge, such as iPhone, MacBook, iPad, and their
maximum supported wattage. Buying a power adapter with a higher wattage than what your devices support is not beneficial and would be a waste of money.
2. Data transfer speed
The faster the transfer speed, the higher the price. If you have a need to
transfer large files to your computer, then you’ll require a faster transfer speed.
For instance, the
iPhone 15 Pro supports
USB 3 with 10 Gbps transfer speed, so the cable also needs to support this speed for fast transfers.
On the other hand, the
iPhone 15 only supports
USB 3 with 480 Mbps transfer speed. So, even if the cable has a higher transfer speed, it won’t make a difference if your device doesn’t support it
3. Cable Length
Aside from considering the cable length for
storage and its
proximity to the charging device, longer cables may experience ‘signal attenuation,’ leading to reduced transmission efficiency. So, longer isn’t always better; you should choose a cable length that suits your needs."
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