This part is a kind of semiconductor called Q4008L4.

Function of this product has Triacs.

Manufacturers : Teccor Electronics

Image and pinout :

Some of the text within the PDF file :

l Se ec te U. L. G 39 CO 716 E R #E d Fi le Pa a ck ge s* Z NI ED E2 TO-92 TO-202 *TO-220 3-lead Compak TO-263 D2Pak TO-252 D-Pak TO-251 V-Pak *TO-3 Fastpak MT2 MT1 G Triacs (0.8 A to 35 A) E2 General Description These gated triacs from Teccor Electronics are part of a broad line of bidirectional semiconductors. The devices range in current ratings from 0.8 A to 35 A and in voltages from 200 V to 1000 V. The triac may be gate triggered from a blocking to conduction state for either polarity of applied voltage and is designed for AC switching and phase control applications such as speed and temperature modulation controls, lighting controls, and static switching relays. The triggering signal is normally applied between the gate and MT1. Isolated pac [ ... ]

Q4008L4 PDF Datasheet Download