Also, with the increase in data rate comes an increase in bus power , i. However, like its predecessor, USB 3. In every instance, when dealing with power and electronic devices, power matters. This includes USB standards, and it is evident by the increase in functionality as the standards evolved.
For example, with USB 1. However, with USB 2. These increases in functionality correlate with the increase in data rates and the improvements in output power. Now, with the USB 3. This, of course, affords USB a myriad of new uses, including system backups, increased gigabit Ethernet adapter performance, and the ability to handle large video files. In any USB network, there is one host and at least one device.
In nearly every instance, a computer is the host, whereas a tablet, camera, or smartphone is the device. Moreover, the flow of power is always from host to device, but data can flow in either direction. Take, for example, connecting your smartphone to your laptop to transfer music files or photos. However, USB 3. With regards to the actual current mA or milliamps , there are three types of USB ports we reference by its current specifications.
They include a dedicated charging port, a charging downstream port, and a standard downstream port. Moreover, the dedicated charging port is what we call a wall charger.
Doktoro Reichard Doktoro Reichard 5, 5 5 gold badges 33 33 silver badges 41 41 bronze badges. Some motherboards have ultra high ampage USB ports to support charging devices off them also. The values need to be standard of course, there exists a certain level of tolerance in the current and voltage levels.
I usually see a lightning-bolt signal in the outside of the port, that should mean the high-discharge port. As for certainty, check the laptop's documentation. Lawrence, that's charging downstream port , which allows the device to draw more than 1 unit without negotiation. As far as I understood, this is not the complete answer as of now. Or do I get it all wrong? PavelGatilov The answer is still accurate regarding the older current ratings, which still apply, although it does need some revision due to recent developments.
USB 2. Power Delivery devices are also supposed to implement some sort of management capability, such that they can revert to older protocols. Show 3 more comments. Grandswiss Grandswiss 1 1 silver badge 2 2 bronze badges. Just be careful that the device and its control circuitry can handle the extra current! As long as the device is getting the correct voltage "electrical pressure" of 5 volts, the available amps can be any amount.
Consider how you can take a home's internal wiring which is capable of many, many amps, enough to power a whole household , wire a 60W lightbulb straight into it, and it'll only draw the power it needs, because it's rated for that voltage V AC. Andrew absolutely wrong. A supply of X amps can supply anything up to X amps.
The device only draws what it needs. Where there may be an issue is when it's the other way around, if a device wants more amps than the supply can put out. If your adapter has 4x more amperes than required it may be able to charge 4 devices at the same time but there won't be any change in the time of charge of a single device.
Not because "it's rated" but because it's a physical law Ohm's Law — runlevel0. USB standard defines two classes of USB ports, "high-power ports", and "low-power ports" The specs says, page "Systems that obtain operating power externally, either AC or DC, must supply at least five unit loads to each port.
What is likely was that this particular model offered a "USB Charging" port. So you can still be in-standard while delivering far, far more power than this - up to watts. Ashley Poland has been writing since She has worked with local online businesses, supplying print and web content, and pursues an active interest in the computer, technology and gaming industries.
In addition to content writing, Poland is also a fiction writer. She studied creative writing at Kansas State University.
Home Hardware. It also supports a power draw of 1. USB-C is a different connector entirely. But there can also be older-style USB ports that support the 3. Now, this is what the spec dictates. There is a huge variance, then, between normal USB ports rated at mA, and dedicated charging ports, which range all the way up to 3,mA. This leads to an important question: If you take a phone which came with a mA wall charger, and plug it into a 2,mA iPad charger, as an example, will it blow up?
In short, no: You can plug any USB device into any USB cable and into any USB port, and nothing will explode — and in fact, using a more powerful charger should speed up battery charging.
The longer answer is that the age of your device plays an important role, dictating both how fast it can be charged, and whether it can be charged using a wall charger at all. Shortly thereafter, USB devices that implemented this spec started to arrive. It might only work with old-school, original mA USB 1.
In some much older cases, USB devices can only be charged by computers with specific drivers installed, but this is now going back nearly two decades. USB-C is a special case. How do you know what the right USB-C cable is?
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