议价SN74LS686NTL052IPUDZVTE¥3.30去看看永恒电子元器件发布了议价装TL052IP CDBKB455KCAY16-R0 SN74LS686N UDZVTE-178.2B比较器SN74LS686NTSN74LS240N逻辑¥30去看看富兴微电子发布了SN74LS686NT DIP24 SN74LS240N S640N S442N S445N逻辑IC比较器