That varies dramatically depending on the revision of the USB used on the port.
Yes. USB can support 127 devices per port which allows for daisy chaining.
USB 1.0 provides a voltage of 5 volts and a current rating of 100 mA for low-power devices. For devices requiring more power, USB 1.0 can supply up to 500 mA when using a powered hub. This standard allows for basic data transfer and charging capabilities for compatible devices.
Through the wire.
It doesn't matter what is the speed is on the USB it depends on the computer's speed on its hardrive, internet, or both the speed is not based on the 2.0 USB, is the computer either its old or new or in between.
If wired correctly, this will not damage the fan or the USB port, as the fan will take less current at a lower voltage. The main problem with this arrangement is the fan would either not start, or would run very slowly, so probably useless for cooling anything. If you can get a 5V fan, not more than 500mA, this would be much more effective. (Note- If wired incorrectly, reverse polarity could damage both USB port and fan, short circuit could damage your USB port.)
Using active hubs you can connect 127 devices to each USB port.
Assuming your using a USB port to power your device, the answer is 2.5 Watts. A maximum of 500mA at 5V can be drawn from a Usb port. Power = Current * Voltage, which is 2.5 Watts by 0.5 Amps giving you a power output of 2.5 Watts http://en.wikipedia.org/wiki/USB#Power http://en.wikipedia.org/wiki/Power_(physics)#Average_electrical_power_for_AC
u can connect a 4 port adapter to a single usb port but if u are using all for ports u may experience slow data transfer
Yes, a USB port can supply a small amount of power for attached devices.
USB 3.0 ports can deliver up to 4.5 watts (5 volts at 900 milliamps) of power. This is an increase from USB 2.0, which provides up to 2.5 watts. Additionally, USB 3.0 supports the possibility of higher power delivery when using specific extensions or configurations, such as USB Power Delivery (USB PD).
The USB port on your lamp may not be working due to a faulty connection, a damaged port, or a power supply issue. It is recommended to check the port for any physical damage, try using a different USB cable or device to test the port, and ensure that the lamp is receiving power properly. If the issue persists, it may require professional repair or replacement.
The output voltage available at a USB port is controlled by the regulator in the computers power supply. It is fixed, you can not change or control it. The maximum current which should be drawn from a USB2 port is 500mA, from a USB3 port it can (I believe) be up to 850mA.
Usually you plug something in to the USB port to either give it power, or charge its batteries.
USB 1.0 has the maximum speed of 1.5Mbps. USB 1.1 is a bit faster at 12Mbps. USB 2.0 is the fastest currently at 480Mbps. USB 3.0 will be released in 2010 and that will have a maximum speed of 4.8Gbit/s.
A COM port can not be converted to a USB port just by using software. The signal types, levels, protocol, connector type all are different.
Whether or not a USB desk fan will work on an HDTV's USB port depends on the purpose of the port. However, in most cases, it will likely power the fan.
You can charge your Touch by connecting it to any computer's USB port, by using a plug-in USB power supply, or by using some form of USB battery pack. I don't know if any of these fit your definition of "without using a charger".