1、Unit 1That is the degree to which a substance prevents the flow of an electric current through it Resistance That is a material or covering which electricity,heat or heat to go through InsulatorThat allow electricity or heat to go through ConductorThe standard unit of electrical resistance OhmThe st
2、andard unit used to measure how strongly an electrical current is sent around an electrical system voltageTwo pieces of wire were connected end to end SeriesTwo pieces of wire were connected side by side ParallalThe standard unit of measurement for the strength of an electrical current AmpereA stand
3、ard or accepted way of doing or making something ,the items needed for it ,or a mathematical rule expressed in a set of numbers and letters FormulaThe standard measure of electrical power wattage1. resistors are used to control voltages an currents.电阻器被用于控制电压和电流2. resistors are components that have
4、a predetermined resistance.resistance determines how much current will flow through a component.电阻器是预先设定好电阻的原件，电阻的大小将决定流过电阻器的电流大小。3. a very high resistance resistor allows very little current to flow.很大的电阻允许很小的电流流过。4. sparks and lights are brief displays of current flow through air .the light is cre
5、ated as current burns parts of the air.闪电是电流流过空气的现象，光是由于电流击穿空气而形成的5. metals have very low resistance .a low resistance allow a large amount of current to flow.金属的电流很小，很小的电阻允许很大的电流流过。6. that is why wires are made of metal.they allow current to flow from one point to another point without any resistan
6、ce .wire are usually covered with rubber or plastic.这就是电线为什么要用金属制成，他们允许电流流过而没有任何阻抗，电线通常外面裹着橡胶或塑料。7. high voltage power lines are covered with thick layers of plastic to make them safe,but they become very dangerous when the line breaks and the wire is exposed and no longer separated from other thing
7、s by insulation.为了安全，高压电线外面要包一层很厚的塑料，当电线折断并且裸露，不再被绝缘体隔离时是非常危险的。8. making the resistance higher will let lexs current flow so the volume goes dowm.当电阻调大时，流过的电流迅速减小。9. variable resistors are also common components.they have a dial or a knob that allows you to change the resisitance.可变电阻器也是普通元件，他们有一个刻度
8、盘或一个旋钮可供调节阻值。10. for example,a 500 variable resistor can have a resistance of anywhere between 0 and 500.例如，一个 500 的可变电阻器，他的阻值可以在 0-500 之间任意调节。Resistance is given in units of ohms.(ohms are named after Mho Ohms who played with electricity as a young boy in Germany.)common resistor values are from 10
9、0 to 1000000,each resistor is marked with colored stripes to didicates its resistance.to learn how to calculate tht value of a resistor bu looking at the stripes on the resistor.电阻的大小是通过欧姆数来说明的（欧姆数是以曼汉姆，欧姆的名字命名的，当让还是一个孩子的时候就在德国从事电方面的工作了） 常用的电阻器的阻值是 100-100000，每个电阻器通过印在上面的色条来表明他的阻值的大小，通过查看色条就可以知道电阻器阻
10、值的大小。Uint 2Stable subatomic particle in the lepton family having a rest mass of 9.106*10e-28 gram and a unit negative electric charge of approximately 1.602*10e-19 coulomb.ElectronA colorless,highly flammable gaseous element the lightest of all gases and the most abundant element in the universe,use
11、d in the production of synthetic ammonia and methanol ,in petroleum refining ,atomic number 1HyclrogenTh net measure of this property possessed by a body or contained in a bounded region of space Charge A part or particle considered to be an irreducible constituent of a specified system AtomHaving a
12、 volume equal to a cube whose edge is of a stated length CubicAn electric generator that produces alternating current AlternatorOf or relating to magnetism or magnets MagneticThe natural force of attraction exerted by a celestial body,such as earth ,upon objects at or near its surface,tending to dra
13、w them toward the center of the bodyGravityA unit of potentical difference equal to one thousandth of a volt MillivoltA building or group of buildings for the manufacture of a product Plant 1. a glass rod becomes charged when rubbed with silk, as does a hard-rubber rod when rubbed with fur.和硬橡胶棒与毛皮一
14、样，玻璃棒与丝绸摩擦可以使玻璃棒带有电荷。2. people found that charges produce rorces of repulsion and attraction. these are usually small forces .人们发现电荷间存在排斥力和吸引力，这种力通常很小。3. negative charges repel negative charges ,positive charge repel positive charges ,and positive and negative charges attract each other, in short ,l
15、ike charges repel and unlike charges attract.负电荷排斥负电荷，正电荷排斥正电荷，正负电荷相互吸引，简言之，同种电荷相互排斥，异种电荷相互吸引。4. on further study of charges scientists found that all negative charges are integer multiples of a certain very small charge.通过对电荷的进一步研究，科学家发现所以的负电荷的电荷量都可以看做是一个整数和一个很小的电荷量的乘积。5. scientist also discovered
16、that positive charges are integer multiples of a very small charge ,the same charges are an electron-but positive the proton has this charge.科学家还发现正电荷也可以看做一个整数与一个很小的电荷量的乘积，电荷量的大小与电子相同，质子也具有这样的电荷。6. rubbing a glass rod with a silk cloth or a hard-rubber rod with fur does not create charge .in general
17、 ,charge cannot be created or destroyed ,a fact called the law of conservation of charge .玻璃棒与丝绸摩擦或是硬橡胶棒与毛皮摩擦并不创造电荷，通常电荷不能创造也不能消亡，这就是电荷守恒定律。7. rubbing the glass rod with a silk cloth removes electrons from the rod and puts them on the cloth . this charge transfer causes a charge unbalance on both th
18、e rod and cloth.玻璃棒与丝绸摩擦使得电子由玻璃棒运动到丝绸上，这种电荷的移动，使得棒与丝绸的电荷失去平衡。8. electrons of an atom have orbits at different distances from the nucleus . for some atoms the electrons in the farthest orbits have only weak forces binding them to the atoms.原子内的电子在离核不同的位置上绕核运动，在某些原子钟对离核最远的电子只有微弱的力将其束缚在原子内。9. an atom w
19、ith an unbalance charge is called an ion. Ions are charged particles that would produce a current if they could move.带有不平衡电荷的原子核称为离子，离子是一种带电荷粒子，如果将离子移动就可以产生电流。10. even at normal room temperatures the outer electrons in metals receive enough heat energy to become free, especially for silver ,copper ,
20、gold ,aluminum. 即使在正常的室温下，一些金属特别是银，铜和金和铝的外层电子也能够获得足够的热量变成自由电子。The charge of an electron or of a proton is much too small to be basic quantity of charge for almost all practical applications . the si unit of charge si the coulomb, with the symbol c.a coulomb of negative charge equals that of 6.42*10e
21、18 electrons .the coulomb is a derived si unit ,which means that it can be derived from si base units.对于所有的具体应用，用电子或质子的电荷量作为电荷的基本单位太小了，国际单位制中电荷的单位是库伦，符号是 c,1 库伦电荷与 6.242*10e18个电子的电荷量相等，库伦来自国际单位制，这意味着它可以由国际单位制中的基本单位导出。Unit 3a closed path followed or capable of being followed by an electric current Ci
22、rcuitA device used to break or open an electric circuit or to divert current from one conductor to another SwitchA position in a circuit or device at which a connection is normally established or broken terminalAn instrument , such as galvanometer ,for measuring potential differences in volts Voltme
23、terAn instrument thea measures electric current AmmeterA device that generates light ,heat, or therapeutic radiation LampA device that converts any form of energy into mechanical energy, especially an intermal-combustion engine or an arrangement of coils and magnets that converts electric current in
24、to mechanical powerMotorScientist who specializes in physics PhysicistThe work required to bring a unit electric charge ,magnetic pole ,or mass from an infinitely distant position to a designated point in a static electric magnetic ,or gravitational field ,respectivelyPotentialThe international stan
25、dard unit of length , approximately equivalent to 39.37 inches ,it was redefined in 1983 as the distance traveled by light in a vacuum in 1/299 792 458 secondMeter1. a power supply could be something as simple as a 9v battery or it could be as complex as a precision laboratory power supply.电源现可以是像 9
26、v 电池一样简单，也可以像实验室的精确电源一样复杂。2. variable resistors are common components .they have a dial or a knob that allows you to change the resistance. This is very useful for many situations.可变电阻是常用的元件，它有一个刻度盘或一个旋钮用于改变电阻，在很多的场合是非常有用的3. diodes are components that allow current to flow in only one direction .the
27、y have a positive side and a negative side.二极管是一种只允许电流以一个方向流过的元件，它有一个正极和一个负极。4. LEDs use a special material which emits light when current flows through it . unlike light bulbs ,LEDs never burn out unless their current limit is reached. LED 使用当有电流流过时就发光的特殊材料制成的，同灯泡不同的是，只要电流在一定的限度内，光不会熄灭。5. well the
28、letter L stands for inductance. The simplest inductor is consists of a piece of wire .字母 L 代表电感，最简单的电感器由一段导线组成。6. two metallic plates separated by a non-conducting materical between them make a simple capacitor.不可导的物质隔开两块金属板就可以形成一个简单的电容器。7. the time required for a capacitor to reach its maximum char
29、ge is proportional to the capacitance value and the resistance value.电容的充电时间同他的电容值和阻抗成比例。8. when AC current flows through an inductance a opposite emf of voltage develops opposing any change in the initial current .当交流电流过一个电感，会产生一个方向的电动势或电压来阻止原来的电流的变化。9. reactance is the property of resisting of imp
30、eding the flow of AC current or AC voltage in inductors and capacitors.电抗是一种抵制或阻止电感器或电容器中的交流电流或交流电压的属性。10. to produce a drift of electrons ,or electric current along a wire it is necessary that there be a difference in “pressure” or potential between the two ends of the wire this potential differenc
31、e can be produced by connecting a source of electrical potential to the ends of the wire.为了产生电子漂移或电流，必须在一条导线的两端有不同的压力或电动势，这种不同的电动势可以通过导线的两端接上电压源来产生。Switches are devices that create a short circuit or an open circuit depending on the state of the switch.for a light switch ,ON menas short circuit (cur
32、rent flows through the switch ,lights light up ).when the switch is OFF, that means there is an open circuit (no current flows,lights go out ).when the switch is ON it looks and acts like a wire .when the switch is OFF，there is no connection .开关是一种根据开关位置来接通或断开电路的设备，对于电灯开关，ON 意味着接通，电流流过开关，灯点亮，当开关在 OF
33、F 位置时，意味着开关没有电流流过，灯熄灭，当开关是 ON 时，它看起来和起的作用就像一根导线，当开关是 OFF 时，就相当于导线没有连接。Unit 4An electronic device that restricts current flow chiefly to one direction DiodeA small electronic device containing a semiconductor and having at least three electrical contacts , used in a circuit as an amplifier, a detecto
34、r ,or a switch TransistorAny of various solid crystalline substances ,such as germanium or silicon, having electrical conduciviy greater than insulators but less than good conductors SsemiconductorA homogenous solid formed bu a repeating ,3 dimensional pattern of atoms ,ions ,of molecules and having
35、 fixed distances between constituent parts .CrystalA tabular arrangement of the elements according to their atomic numbers so that elements with similar properties are in the same columnPeriodic tableSomething ,such as a fettet, cord ,or band ,that binds ,ties ,or fastens things ,together. BondA mat
36、erial that insulates ,especially a nonconductor of sound ,heat, or electricity. InsulatorA rectangular array of numeric or algebraic quantities subject to mathematical operations. MatrixA compound with two oxygen atoms per molecule DioxideThe quality or condition of being impure ,especially. Impurit
37、y1. generally transistors fall into the category of bipolar transistor, either the more common NPN bipolar transistors or the less common PNP transistor types .一般的晶体管都属于双极晶体管， ，要么是属于比较常用的 NPN 型双极晶体管，要么是使用较少的 PNP 型晶体管2. silicon crystals for example have very free electrons .however if “impurities”(di
38、fferent atomic structure-e. g. arsenic) are introduced in a controlled manner then the free electrons or conductivity is increased.例如，硅晶体只有很少的自由电子，但是如有以一钟可控制的方法掺入杂质， （原子结构不同，例如砷） ，则自由电子或可导性就增加了3. if we take a piece of the p-type material and connect it to a piece of n-type material and apply voltage
39、 then current will flow . electrons will be attracted across the junction of the P and N material.如果将一块 N 型材料同一块 P型材料相连，然后加上电压，将有电流流过，电子将被吸引穿过 PN 结构的材料4. a silicon flake a quarter inch on a side can hold a million electronic components ,ten times more than 30 ton ENIAC, the worlds first electronic d
40、igital computer.边长是 1/4 英寸的硅片可以容纳 100 万个电子元件，是 30 吨中的电子计算机 ENIAC 元件数量的 10 倍，ENIAC 是世界上第一台电子数字计算机5. a microprocessor , for example ,can endow a machine with decision with decision-making ability, memory for instructions ,and self-adjusting controls.例如微处理器，可以赋予一台机器决策的能力，指令的存储及自适应控制6. eventually one bi
41、llion transistors, or electronic switches, many crowd into a single chip. A memory chip of such complexity could store the text of 200 long novels.10 亿个晶体管或电子开关最终可能集中到一个芯片上，如此复杂的存储芯片可以储存 200 部长篇小说的内容7. a transistor can be configured as a diode and often are used in certain projects, especially to ad
42、just for thermal variations 一个晶体管可以被设置为一个二极管并且常被用于某些工程，尤其是用于调节热量变化8. a transistor is often a limitation and at other time an asset that with zero spacing between the P and N junctions we have a relatively high value capacitor.半导体常常作为一个限定器，有时他的优点是：当 PN 结之间的距离为零时，我们可以得到一个相对容量较大的电容9. the early principa
43、l application of diodes was in rectifying 50/60HZ AC mains to raw DC which was later smoothed by choke transformers or capacitors.早起的二极管的主要应用是将 50/60HZ 的交流电整流为粗糙的直流电，然后通过扼流变压器或电容进行平滑处理。10. varactor or tuning diodes work on the principle that all diodes exhibit some capacitance.变容二极管或调谐二极管的工作原理是，所有的二
44、极管都表现出一些电容的特性the transistor was developed at bell laboratories in 1948. large scale commercial use didnt come until much later owing to slow development . transistors used in most early entertainment equipments were the germanium types . when the silicon transistor was developed it took off dramatic
45、ally. The first advantages of the transistor were relatively low power consumption at low voltage levels which made large scale production of portable entertainment devices feasible .interestingly the growth of the battery industry has paralleled the growth of the transistor industry.晶体管于 1948 年由贝尔实
46、验室开发，由于发展的缓慢直到很久以后才进行大规模的商业用途，早期大部分的娱乐设备使用的晶体管是锗型的，当硅型晶体管发展起来以后，很快就不用锗型晶体管了，晶体管的一个最重要的优点是工作电压想对较低，能耗相对也低，因此能够利用它制造大量便携的娱乐设备，有趣的是电池工业正好同晶体管工业同步发展。Unit 5 Knowledge of a specific event or situation; intelligence InformationOf or relating to a number or series of numbers NumericalThe combination of qual
47、ities or features that distinguishes one person ,group,or thing from another CharacterOr or relating to a sys tem of numeration having 2 as its base BinaryA number written using the base 10;numerical DecimalOf ,relating to ,or based on the number 16 HexadecimalBinary coded decimal BCDThe letters of
48、a language ,arranged in the order fixed by custom alphabetThe number that is raised to various powers to generate the principal counting units of a number systemBaseThe number left over when one integer is divided by another Remainder1. because a single bit can only store two values ,bit are combine
49、d together into large units in order to hold a greater range of values.由于一位只能存储两个值，因此要用许多位组合成大的单元来存储较大范围的值2. Boolean variables use a single bit to hold their value ,so can only assume one of two possible states 布尔变量用一位来保存它的值，所以只能表示两种可能的状态之一3. consider where a computer allocates 16 bits of storage per status variable. If we had three status variables ,the space consumed would be 48 bits.鉴于计算机每个状态变量分配 16 位存储空间，如果我们有 3 个状态变量，就需要48 位的存储空间4. ASCII is a computer code which uses 128 different encoding combinations of a group of seven bit (2*7=128)to represent ASCII 码是一种计算机编码，它由一组 7 位组成的 128 钟不同的二进
