What type of power flaw involves a fluctuation in voltage levels caused by other devices on the network or by emi? ?

noise

Noise is a troublesome disruption in an electrical signal. It is caused by electronic gadgets. There are five types of noise depending on the source (various devices and processes) which includes thermal noise, shot noise, flicker noise, burst noise or transmit-time noise. It can also come as a coupled noise from the outside environment.