Semiconductors?
The BTA204-600D127 part from NXP Semiconductors is a PN-PNDIODE, totally diffused, 600V, 4A, 120ns. This 700mA current rated diode is molded in a TO-220AB hermetically sealed package. It has a breakover voltage of <4V and a low-tolerance threshold voltage. The diode is designed for use in applications such as the protection of power supplies, the switching of motors, mains filtering, snubbers and a variety of other AC/DC applications.