emi in electronics

EMI stands for Electromagnetic Interference. It is what happens when electrical signals that are sent by one electronic device, like a phone or a computer, can interfere with signals from other electronic devices. For example, if you have a phone that is sending a signal out and another device, like a TV, can pick up and be affected by that signal, then that's what EMI is. To prevent EMI, manufacturers build things in such a way that electrical signals don't interfere with each other.