Alternistor Snubberless — no RC snubber needed for inductive loads
The ST BTA12-800CWRG is an Alternistor-Snubberless TRIAC rated for 800 V off-state voltage and 12 A RMS on-state current. The Snubberless™ construction means it commutates inductive loads — motors, solenoids, transformers — without the external RC snubber that standard triacs need, saving two components and a chunk of board area. It lives in a TO-220AB insulated package (the tab is electrically isolated, so you can bolt it to a shared heatsink without an insulating pad).
800 V off-state and 12 A RMS — sizing the load and the heatsink
The 800 V Vdrm gives you headroom on a 240 VAC line (peak ~340 V) or even a 480 VAC line-to-line (peak ~680 V) with margin. The 12 A RMS continuous rating sets the load power: at 240 VAC that is roughly 2880 W resistive, but inductive loads need derating for power factor and inrush. Gate trigger current is 35 mA max, gate trigger voltage 1.3 V max — a standard logic-level optocoupler or a small-signal transistor can drive it directly. Holding current is also 35 mA max, so it stays latched once triggered unless the load current drops below that threshold. Non-repetitive surge current is 120 A at 50 Hz, 126 A at 60 Hz — that is the peak the die can survive for one half-cycle. Useful for capacitive loads or motor start where the inrush can be 10× the steady-state current.
Active production, ROHS3, through-hole package
The tab is electrically isolated, which simplifies heatsinking in a metal enclosure — no mica washer needed, just thermal compound.