Q:

Powering a Line Laser 5V 200mA using USB port

I have a IR Line Laser with following Specs
Output Power    : 60mw
Wavelength      : 780nm
Working Voltage : 5.0VDC
Working Current : <200mA
Laser Shape Line
for details please visit the link http://www.aliexpress.com/item/60mw-780nm-Infrared-Laser-Line-Module-120-degrees/1517656084.html
i would like to power this device using a USB port via a cable. iknow USB has an output voltage 5V but isnt it 500mA ?? Some say Device draws only required current from USB port
My question is can i directly connect laser to USB port by cutting a USB cable? Or should i convert 500mA to 200mA? If so how can i do it ? Can someone specify a solution?
Thanks in Advance

A:

Well, if you are looking for a quick fix, you can go ahead and plug it into USB. Although a Fuse (200mA) in series with the diode might help. This is good solution only if you are going to use it for very short duration like few hours (continuous use).
But if you want to use it continuously for a very long time like days, this might affect the motherboard of your PC (as the continuous current might lead to heat). If you are using a laptop, there will be side effects on the battery for sure.
So depending on your application, one might or might not suggest you to use a USB as power source.

