is an electronic device/component really burn?
In English, "burnt" is often used loosely to indicate a part got damaged by something excessive done to it, not necessarily actual combustion.  It can also be said that a part is "toast", "got fried", "smoked", and a few others.  These expressions are not meant to be taken literally.

In most cases, damage to electronic parts due to excessive current or voltage results from the excessive heat caused locally, but not always.  Even so, this heat is rarely due to combustion, just heat from current times voltage.