1. Triac Type and Structure: MAC4N: Standard triac. Its internal structure is the conventional PNPN NPNP five-layer semiconductor, which is relatively sensitive to the rate of voltage change (dv/dt) in the off-state. T435-800T: Alternistor – Snubberless™. Its internal structure is optimized, integrating functionality analogous to a snubber circuit, and offers very high static and dynamic dv/dt immunity. This is the most critical distinction. The T435-800T is specifically designed for driving inductive loads (e.g., motors, transformers, solenoids). During turn-off, it effectively suppresses transient high dv/dt generated by circuit inductance, preventing false triggering. This often allows the omission of an external RC snubber network, simplifying design and saving cost and board space. When the MAC4N is used in similar applications, an external RC snubber circuit is mandatory to ensure stable operation. 2. Surge Current Capability (Itsm): MAC4N: 40A @ 60Hz. T435-800T: 30A, 31A (typically corresponding to different cycle count test conditions). The MAC4N has a higher absolute non-repetitive surge current withstand capability (approximately 33% greater). In scenarios involving extreme overload or short-circuit faults, the MAC4N may have a marginally higher probability of survival. This difference should be considered for designs subject to frequent high inrush surges or those requiring very high safety margins. Additional Note: The triggering characteristics (Vgt, Igt, Ih) and rated current/voltage are identical for both devices, ensuring driver circuit compatibility for direct substitution.