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这里介绍的电子设计——数字钟不但具有一般的设定时间功能,同时具有能在一天之内,按指定的编程定时,对任何电子设备、家用电器(最多可达八个设备),进行任意次数的通(on)和断(off)。 图1所示为数字钟的框图。此钟有两个组成部分:数字钟部分和编程部分。图2所示为数字钟部分的电路图,而图3所示就是编程部分的电路图。 定时器IC555(IC17)用做自激多谐振荡器,所设计的振荡频率为100Hz。两个十进计数器7490(IC18和IC19)将此频率除以100因此,
The electronic design introduced here - the digital clock not only has the usual time-setting function, but also has the ability to carry out any of the electronic devices, home appliances (up to eight devices) at a specified programming timing in one day The number of on (on) and off (off). Figure 1 shows the block diagram of the digital clock. This clock has two components: the digital clock part and the programming part. Figure 2 shows the digital part of the circuit diagram, and Figure 3 shows the programming part of the circuit diagram. Timer IC555 (IC17) used as a self-excited multivibrator, the design of the oscillation frequency of 100Hz. Two decimal counters 7490 (IC18 and IC19) divide this frequency by 100 Therefore,