10 A phase-control SCR with 800 V blocking
The STMicroelectronics TYN816RG is a standard-recovery SCR in a TO-220-3 through-hole package, rated for 800 V off-state voltage and 10 A average on-state current. This is the go-to thyristor for medium-current phase-control circuits, AC motor soft-starters, and industrial power supplies where the 16 A RMS rating provides headroom for continuous loads. The 25 mA maximum gate trigger current and 1.5 V maximum gate trigger voltage mean a standard microcontroller I/O pin driving through a resistor can fire it directly — no separate driver IC needed in many designs.
Gate drive and surge margin
Gate trigger current is specified at 25 mA max; in practice, design for at least 30 mA to guarantee turn-on over temperature and part variation. The 40 mA holding current ensures the SCR latches cleanly once triggered and stays on until the load current drops below that threshold. Non-repetitive surge current is 160 A at 50 Hz and 167 A at 60 Hz — this covers inrush from capacitive loads or fault events. The 5 µA max off-state leakage at 125°C is tight enough to avoid nuisance turn-on in high-impedance gate-drive circuits.
The TO-220 tab allows bolting to a heatsink for continuous 10 A average conduction — the on-state voltage drop of 1.6 V max at 10 A means about 16 W dissipation that must be sunk.
No official second-source or successor is listed, so the BOM depends on this exact ST part.