Sensitive-gate triac for logic-level AC switching
12 A RMS load current and surge capability
The 12 A RMS continuous rating covers resistive loads like heaters, incandescent lamps, and small motors up to about 2.5 kW on 230 VAC lines. Non-repetitive surge current is 120 A at 50 Hz and 126 A at 60 Hz — enough to handle inrush from motor starts or cold-filament lamp strikes without exceeding the die's thermal capacity. Holding current (Ih) is 15 mA maximum. Below this load current the triac will commutate off at zero-cross; designs driving very light loads — below 15 mA — may need a dummy resistor to guarantee latching.
The BTA12 base number is a long-running ST power-logic family; replacement risk is low for the foreseeable production horizon.