The ST TS110-8A1-AP is a sensitive-gate silicon controlled rectifier (SCR) rated for 800 V off-state voltage and 1.25 A RMS on-state current, housed in a through-hole TO-226-3 (TO-92-3) package. Its 100 µA maximum gate trigger current makes it suited for low-power switching circuits driven directly by microcontrollers, sensors, or logic-level outputs. Typical applications include small motor controls, lighting dimmers, heater drives, and capacitive discharge igniters in industrial or appliance environments.
Gate trigger current — the 100 µA edge
The 100 µA maximum gate trigger current (Igt) is the key feature that distinguishes this part from standard SCRs. The 800 mV maximum gate trigger voltage (Vgt) means a 3.3 V logic high comfortably exceeds the threshold, even with a series current-limiting resistor.
The 800 V off-state voltage (Vdrm/Vrrm) provides ample margin for 240 VAC mains circuits, rectified to about 340 V peak. The 1.25 A RMS on-state current (It(RMS)) and 800 mA average (It(AV)) suit loads like small solenoids, relays, or incandescent lamps. The non-repetitive surge current rating of 20 A at 50 Hz and 21 A at 60 Hz (Itsm) covers inrush from capacitive or filament loads — a critical spec for reliability in lighting and power supply applications.
The 1 µA maximum off-state leakage at 25°C (Idrm/Irrm) keeps quiescent power loss negligible in standby circuits.