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1.4 思考题与习题
1. 说明数字电路和模拟电路的区别及各自特点。
2. 什么是逻辑变量?什么是逻辑函数?
3. 基本逻辑运算有哪几种?每种逻辑运算的逻辑表达式是什么?
4. 什么是逻辑函数的最简与或表达式?
5. 照明电路如图1-28所示,设灯亮L=1,开关A和B闭合为1,试写出灯点亮的逻辑表达式。
6. 用逻辑表达式描述出图1.29中灯L点亮与开关K1、K2、K3动作之间的关系,开关闭合为1。
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0034_0002.jpg?sign=1739253535-U8XgLWisRjCaU8p3yCLNc4sz0pebEcBM-0-6726d22ce741f366819bf0ee22352a0c)
图1-28
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0034_0003.jpg?sign=1739253535-Jevuir1U5RkazLjGSnW0YI7VYEpWQfWx-0-32a326aaafa5df4c769125e00929bac2)
图1-29
7. 将下列函数化简为最简的与或表达式。
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0034_0004.jpg?sign=1739253535-Nc0lO6LNvztbNXhzhWX5PbBM3VRyjYIS-0-de1907d68931afeb6ff5349a6ea428e1)
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0034_0005.jpg?sign=1739253535-An1clTa47nhh9OZau9RuMe1MyrJmZunD-0-840bf26077ab58d3a2c51ce410227637)
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0034_0006.jpg?sign=1739253535-Y8N5SEKSWZ1yItm1Sb9UdCdOvSydtxOH-0-e24a7d5367b545677301a9195ae1ee66)
(4)Y=A·B+B+B·C·D
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0034_0007.jpg?sign=1739253535-TXEFB8mEVLpiycgHx9BGjusQO5oTmEgG-0-1f6de19f86141afb5d6879139de81915)
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0035_0001.jpg?sign=1739253535-9PBod5yH2PWWeLQN3pqC6U2CJmgmTzvD-0-14af1ee3fd8695d71325b81ce2110320)
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0035_0002.jpg?sign=1739253535-bltSFElWpbnF6ud3vCk7KhDiz64jGeBe-0-d697fb399e7f1a17b05a6d7a4200e48c)
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0035_0003.jpg?sign=1739253535-WozrfXJHhzBtU3uXJlsZ6ErxREXzMTLN-0-8f3b3d2d4a03592fdcd8e068951d19a5)
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0035_0004.jpg?sign=1739253535-b1L50tHivBchnbdtbeS2iorulsxDPwNY-0-b456f254cd6d69c38e3aad730b02aac0)
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0035_0005.jpg?sign=1739253535-xAakN4NlwlKr0HnnvfrUfEAcqUQqSQHm-0-d04ab9550ed8e1e13f41fa4541ba0184)
8. 组合逻辑电路的设计步骤是什么?
9. 设计一个A、B、C三人表决电路。当表决某个提案时,多数人同意则提案通过,同时A具有否决权。用与非门实现电路连接。
10. 在计算机系统中,缓冲器和锁存器各起什么作用?
11. 图1.30为一个扩展模块的地址译码电路,为系统总线信号,低电平允许寻址。已知A15~ A10为全0,请写出74LS138的各个输出引脚(
~
)所对应的地址范围。
![](https://epubservercos.yuewen.com/6A81F4/3590548103311201/epubprivate/OEBPS/Images/figure_0035_0009.jpg?sign=1739253535-TAmKIOmSNoaDLAqvk0BlYDw4gWZUBqRk-0-1b2effaefdef85cc152e10d0b3bd5772)
图1-30
12. 简述TTL、MOS数字集成电路的特点及其应用范围。