1. SCR Type: The CZS5064 is a standard‑recovery type, while the S4X8TSRP is a sensitive‑gate type. The gate trigger current (Igt) and voltage (Vgt) required by the S4X8TSRP are easier to satisfy under equivalent conditions, making it particularly suitable for direct control by weak drive sources such as microcontrollers. If the replacement direction is reversed (standard replacing sensitive), triggering failure may occur. 2. Off‑State Leakage Current: The off‑state leakage current of the S4X8TSRP (3 µA) is significantly lower than that of the CZS5064 (50 µA). This indicates that the S4X8TSRP employs superior chip design and process technology, offering lower static power dissipation and better turn‑off characteristics under high temperature or high voltage conditions. This contributes to improved system energy efficiency and thermal stability. 3. Surge Current Capability: The S4X8TSRP clearly specifies its non‑repetitive surge current rating (8 A / 10 A), whereas the CZS5064 does not provide this parameter. This means the S4X8TSRP’s tolerance under transient overload conditions is documented, offering clearer design margin. It is suitable for applications with higher reliability requirements where surge events may occur.