A single event upset (SEU) is a change of state caused by a low-energy ions or electro-magnetic or nuclear radiation or any other kind of interferences that can reach (called ""strike"") a sensitive node in a micro-electronic device, such as in a microprocessor, semiconductor memory, or power transistors. The error in the device output or operation caused as a result of the strike is called a SEU or a soft error. The SEU itself is not considered permanent damage to the transistor's, circuits' or devices'.