If your electronic item is not plugged in, would it still be affected by an EMP?
Yes it will. Electricity is generated when a magnetic field cuts across a conductor. EMP creates an enormous magnetic field. As that field cross the conductive traces and wires of a device, it creates a very large voltage spike. That damages the devices. The Russians built their aircraft with vacuum tube electronics to "harden" them against EMP voltage spikes. The modern semiconductor chips run at very low voltages to avoid arcing between the very closely spaced components. Such devices are VERY sensitive to EMP.