The 1.5KE12A is an ESD (electrostatic discharge) suppression diode produced by Yageo, a prominent supplier of passive components. It is a DO-201 (axial-lead) TVS (transient voltage suppression) device, which mainly functions to protect sensitive electronics from voltage transients caused by ESD. The device is RoHS compliant, meaning that it does not contain hazardous materials like lead. It has a peak clamping voltage of 16.7V, a reverse stand-off voltage of 11.4V and a maximum clamping current of 10.2V. It features a low clamping voltage, a fast response time, and is up to three times more resistant to thermal shock than other types of ESD protection devices.