Bilingual edition: English is preserved and Chinese follows each unit. Terminology uses the confirmed v20260916 glossary; automated semantic review remains traceable. 中英双语版:英文原文完整保留,中文紧随对应单元;术语采用 v20260916 确认表,自动语义审校结果可追溯。
IC7420 Dual 4-Input NAND Gate
IC7420 双4输入NAND逻辑门
The 7420, 74H20, 74S20, 74LS20 share this geometry and function.