Hexton Technologies

The BT169D is a Planar passivated Silicon Controlled Rectifier with sensitive gate in a SOT54 (TO-92) plastic package. This SCR is designed to be interfaced directly to micro controllers, logic ICs and other low power gate trigger circuits.

The standard 12 A SCR series is suitable to fit all modes of control, found in applications such as overvoltage crowbar protection, motor control circuits in power tools and kitchen aids, inrush current limiting circuits, capacitive discharge ignition and voltage regulation circuits.
.
TYN616 is a 16Amp 600V general purpose Silicon Controlled Rectifiers is designed for power supplies up to 400Hz on resistive or inductive load.

A thyristor is a four-layer semiconductor device, consisting of alternating P type and N type materials (PNPN). 

A TRIAC (triode for alternating current; also bidirectional triode thyristor or bilateral triode thyristor) is a three terminal electronic component that conducts current in either direction when triggered.

A thyristor is a four-layer semiconductor device, consisting of alternating P type and N type materials (PNPN). A thyristor usually has three electrodes: an anode, a cathode, and a gate (control electrode). The most common type of thyristor is the silicon-controlled rectifier (SCR).

A Triac is a high-speed solid-state device that can switch and control AC power in both directions of a sinusoidal waveform. Being a solid state device, thyristors can be used to control lamps, motors, or heaters etc.