12 A RMS SCR for line-voltage phase control
The STMicroelectronics TYN612RG is a standard-recovery SCR rated for 600 V off-state blocking and 12 A RMS on-state current, packaged in a TO-220-3 through-hole case. It is designed for phase-control applications such as motor speed controllers, industrial heating, and AC power switching where a robust, medium-current thyristor is needed.
The gate trigger current is 15 mA maximum at 1.3 V maximum gate voltage — a standard drive level that a simple transistor or optocoupler can source. The 30 mA holding current sets a minimum load current floor: below that the SCR may drop out of conduction at the zero-cross. For loads that dip below 30 mA (e.g., a relay coil in series with a bleeder), a dummy resistor across the output ensures the holding current is met. The on-state voltage drop is 1.6 V maximum at rated current, which at 12 A RMS translates to roughly 19 W conduction loss — factor this into heatsink sizing for continuous duty.