The ST BTA24-700BWRG is a 25 A RMS, 700 V off-state Snubberless™ alternistor triac in a TO-220-3 through-hole package. It is designed for AC mains switching of resistive and inductive loads — heating elements, motor starters, lighting banks, and industrial contactor drives — where the Snubberless construction eliminates the external RC snubber network normally needed for inductive turn-off. The alternistor structure handles high dV/dt commutating conditions, so it suits applications like solid-state relays and AC fan speed controllers where the load current and voltage are out of phase.
The 700 V off-state voltage (Vdrm/Vrrm) gives headroom for 230 VAC or 277 VAC mains with typical line transients — no need to derate for nominal line. The 25 A RMS on-state current (IT(RMS)) sets the continuous load ceiling; for a 15 A resistive heater at 230 VAC you have margin, but a motor with locked-rotor inrush needs the surge rating checked. The 250 A / 260 A non-repetitive surge (ITSM at 50/60 Hz) covers cold-filament inrush of tungsten lamps or capacitor charging events. Gate trigger current (Igt) of 50 mA max and gate trigger voltage (Vgt) of 1.3 V max are standard for logic-level or microcontroller-driven optocoupler interfaces — the 75 mA holding current (Ih) means the triac stays latched once fired unless the load current dips below that threshold, which matters for low-power loads like small fans or relays.
It reworks easily — no hot-air profile needed, just a soldering iron with a wide tip and a desoldering station for removal. The tab is the common terminal (MT2), so the heatsink pad is at line potential; use an insulating washer and thermal grease if the heatsink is grounded. No moisture sensitivity level concern for through-hole parts; no bake required before assembly.