800 V off-state, snubberless — what that buys you on a 230 V line
The T835H-8I is a Snubberless alternistor triac from ST's H Series, rated for 800 V off-state voltage and 8 A RMS on-state current in a TO-220AB insulated package. The 800 V rating gives comfortable headroom on a 230 VAC line (325 V peak) — you can absorb line transients up to 800 V without avalanche. The Snubberless construction means no external RC snubber for inductive loads like small motors or solenoids, which saves two passives and a trace route on the PCB.
8 A RMS at 150°C — thermal margin for hot enclosures
The 8 A RMS rating is the continuous load limit, and the 150°C maximum junction temperature lets it run that current in a warm cabinet — think a lighting ballast or a motor drive panel where ambient hits 85°C. The 35 mA gate trigger current (Igt) and 35 mA holding current (Ih) are standard for this class; the 1.3 V gate trigger voltage (Vgt) means a 5 V logic output from a microcontroller or optocoupler drives it directly through a series resistor.
Surge handling and the TO-220AB insulated package
Non-repetitive surge current is 80 A at 50 Hz and 84 A at 60 Hz — enough to survive the inrush from a 100 W incandescent lamp or a small capacitor-input power supply.