在逻辑电路中,单脉冲(特别是窄的单脉冲)用普通逻辑笔或示波器是很难观测到的。这里介绍的一种TTL逻辑笔,仅用一片SN74123集成电路和三支LED就可以检测出从毫微秒级到秒级的单脉冲,还能象普通逻辑笔一样指示出低电平、高电平和低频方波信号(分别见功能表的1.2.3项),并且可以判断脉冲的上升沿和下降沿(表的4.5项)。 In a logic circuit, a single pulse (especially a narrow single pulse) with a normal logic pen or oscilloscope is very difficult to observe. Introduced here, a TTL logic pen, only a SN74123 integrated circuit and three LEDs can detect a single pulse from the nanosecond to the second level, but also the same as the normal logical pen indicates a low, high power Flatten the low frequency square wave signal (see Function Table 1.2.3, respectively) and determine the rising and falling edges of the pulse (Table 4.5).