当前,数字式仪器仪表已经越来越广泛地应用在我们的工作中。但由于开机后计数器、分频器的状态都是随机的,所以在正式工作之前都首先要给计数、分频电路置零。解决这个问题有两个方法:一个是手动置零,那就是在仪器的面板上设置一个置零按钮;再一个就是应用简单的电路实现开机自动置零。本文介绍两种开机自动置零电路。电路结构简单,经济实用,效果很好。 At present, digital instrumentation has been more and more widely used in our work. However, due to boot counter, the status of the divider are random, so before the formal work must first give the count, divide the circuit zero. There are two ways to solve this problem: one is to manually set zero, that is, set a zero button on the instrument panel; the other is to use a simple circuit to automatically zero the boot. This article describes two boot auto-zero circuit. Circuit structure is simple, economical and practical, the effect is very good.