What are some of the effects that power quality might play in the  selection of different devices?  For example, power supplies may be  subject to transients, harmonics, variations in voltage and (sometimes)  frequency and so forth.  Also, what about temperature variations,  vibration, dust, and other environmental challenges. How could we go  about determining which type of device or model of a particular  manufacturer's device might provide superior performance in this area?    Hint:  Check out a few data sheets online and see what types of  specifications you see there.