The 5.0SMDJ26CA is an unidirectional transient voltage suppressor (TVS) diode, manufactured by Yageo, and designed for use in overvoltage protection circuits. It is RoHS compliant and comes in the DO-214AB package. This particular model has a peak pulse power dissipation of 500W. It is used to protect a circuit or system from being damaged by voltages that occur during a power surge or line transient.