400 V blocking, 8 A continuous — phase-control workhorse
The STMicroelectronics TYN408GRG is a standard-recovery SCR in a TO-220-3 through-hole package, rated for 400 V off-state voltage and 8 A RMS on-state current. It is designed for line-voltage phase-control applications such as motor speed controllers, heater regulators, and AC power switching where a simple, rugged thyristor is the right fit.
Surge margin and gate drive
Non-repetitive surge current is 80 A for 50 Hz and 84 A for 60 Hz half-cycle, giving headroom for capacitor inrush or motor start transients. Gate trigger current is 25 mA max and gate trigger voltage is 1.5 V max — compatible with standard optocoupler or pulse-transformer drive circuits without extra amplification.
The TO-220-3 package with a metal tab allows heatsink mounting for continuous 8 A RMS conduction; the tab is electrically common with the cathode.
ROHS3 compliant, no exemptions that would complicate EU or UKCA declarations.