40 A RMS, 700 V — sized for industrial AC switching
The STMicroelectronics BTA41-700BRG is a standard triac in a single configuration, rated for 40 A RMS on-state current and 700 V off-state voltage. That 700 V Vdrm gives real headroom on 230 VAC and 277 VAC mains lines, handling the voltage spikes that come with inductive loads like motors, transformers, and solenoids. The 40 A continuous rating means this part can switch a substantial load — think 10 HP motor drives, large industrial heaters, or welding equipment — but the heatsink and derating curve will determine the actual continuous current in your enclosure. The non-repetitive surge rating of 400 A at 50 Hz and 420 A at 60 Hz covers the inrush from motor starts and capacitor banks without the triac latching into conduction.
Gate drive and hold current — what to expect from the trigger circuit
Maximum gate trigger current is 50 mA, with a maximum gate trigger voltage of 1.3 V. That is a standard sensitivity — a typical microcontroller GPIO through a transistor driver or an optocoupler with a series resistor will fire it cleanly. The 80 mA maximum holding current is on the higher side, which means the triac will reliably commutate off when the load current drops below that threshold; this is helpful in inductive circuits where the load current zero-crossing is not perfectly clean. For low-current loads below 80 mA, you may need a snubber or a different triac with a lower Ih.
TOP-3 insulated package — mounting and isolation
The BTA41-700BRG comes in a TOP-3 Insulated through-hole package (supplier device package TOP3). The through-hole leads handle the 40 A current without the trace-width headaches of a surface-mount part.
RoHS compliance is standard for ST's current triac portfolio; the part carries the standard lead-free finish for the TOP-3 Insulated package.