1. Substitution Conclusion for 1.5SMC13A (Littelfuse Inc.) This part is a viable substitute for the original component (Panjit). Both share identical core electrical parameters: reverse standoff voltage (11.1V), minimum breakdown voltage (12.4V), maximum clamping voltage (18.2V), and peak pulse power (1500W). This ensures fully equivalent protection thresholds and energy absorption capability within the circuit. The only difference is the peak pulse current rating: the Littelfuse part is rated for 83.5A, slightly higher than the original's 82A. This provides a marginally larger theoretical current margin when handling surges of the same waveform, representing a positive and more relaxed design parameter. It will not lead to insufficient protection or premature triggering. Both devices use the DO-214AB (SMC) package, enabling a direct physical replacement. From the perspectives of electrical performance and mechanical compatibility, the substitution is feasible and reliable.