电子工程专业外语考试题.doc

The advantages of the transistor over the vacuum tube wereenormous. Compared totheold technology ,transistors were much smaller ,faster ,and cheaper to manufacture . They were also far more reliable and used much less power . The transistor is what started the evolution of the modern computer industry in motion. 和真空管相比，晶体管存在着巨大优势：晶体管的尺寸小得多，切换速度快得多，生产成本低得多； 晶体管的性能更加可靠，耗能也更少。晶体管的发明带来了计算机工业的蓬勃发展。 A special material is used to make these integrated circuits. While most materials either insulate from electrical flow (air , glass ,wood )or conduct electricity readily (metals ,water ), there are some that only conduct electricity a small amount ,or only under certain conditions . These are called semiconductors . the most commonly used semiconductor is of course silicon . 制造集成电路需要使用一类特殊材料。多数材料要么对电流绝缘（如空气，玻璃，木头），要么很容易传导电流（如金属，水溶液）， 但也有一些材料只能传到少量电流，或只在特定条件下传导电流 ------这种材料被称作“半导体”。 硅是最常用的半导体材料。 A flip-flop is basically a bi-state circuit in which either a 0 or 1 state can resides. beacause its simplicity ,the flip-flop is extremely fast . as a basic element , the flip-flop is used in digital circuits and Ics . A flip-flop will lose its state when the supply votage is removed.Therefore,itis volatile. 触发器是一种存储“0或”1“ 的双态电路。由于结构简单， 所以触发器速度极快。触发器是数字电路和集成电路的基础构件。由于电源电压去掉后，触发器的原有状态就失去了，因此触发器是易失的. RAMstandsforrandom-access memory . RAM contains bytes of information , and the microprocessor can read or write to those bytes depending on whether the RD or WR line is signaled . One problem with today’s RAM chips is that they forget everything once the power goer off . that is why the computer needs ROM . RAM 是随机存取存储器。RAM中包含着以字节为单位的信息，微处理器能够依据RD/WR 信号哪个有效来决定字节的读、写。当前RAM芯片的一个问题是，掉电后，所有保存在RAM上的内容全部丢失。这就是计算机需要ROM 的原因。 The test register is a special latch that can hold values from comparisons performed in the ALU . An ALU can normally compare two numbers and determine if they are epual , if one is greater than the other , etc. The test register can also normally hold a carry bit from the la