12 A, 400 V, 50 mA Igt — the ratings that define the load
The STMicroelectronics BTA12-400BRG is a standard triac in a single-device TO-220 through-hole package. It is rated for 12 A RMS on-state current and 400 V off-state blocking voltage, with a maximum gate trigger current of 50 mA and a maximum gate trigger voltage of 1.3 V. These ratings set the load-switching capacity and the drive sensitivity for AC power control in applications like heater regulation, motor speed control, and lighting dimmers.
Obsolete — sourcing from independent channels
No official successor is recorded.
Gate trigger current and surge capability
The 50 mA maximum gate trigger current (Igt) is a standard sensitivity for medium-power triacs — it requires a driver capable of sourcing that level without dropping below the 1.3 V Vgt threshold.
Hold current and conduction stability
A maximum hold current (Ih) of 50 mA means the triac will latch on as long as the load current stays above that level. If the load current dips below 50 mA near the zero-cross, the device may commutate off prematurely — a consideration for lightly loaded or highly inductive circuits where a snubber network may be needed.