Energy dispersive X-ray analysis is an analytical technique used for the elemental analysis or chemical characterization of a sample.

In combination with a SEM it relies on the interaction of the electron beam with a sample causing X-ray excitation.

Its characterization capabilities are due in large part to the fundamental principle that each element has a unique atomic structure allowing a unique set of peaks on its electromagnetic emission spectrum. The peak positions are predicted by the Moseley's law with accuracy much better than experimental resolution of a typical EDX instrument.

Thus the measured spectra can be evaluated by comparison to theoretical spectra and the elemental composition of the sample can be analyzed.