4. If the project parts list does not specify a voltage, choose a capacitor with a rating which is greater than the project?s power supply voltage.
工程列表中没有说明电容额定电压大小，选择电容时，要选择额定电压大于供电电压的电容。
5. However older ones use a colour-code system which charging/discharging equations.
同时注意有的电路包含多个电源和电阻，此时在电容充电和放电等式中应使用ETh 和RTh。
句中ETh 和RTh 分别表示戴维南等效电压和等效电阻。
has two stripes（for the two digits）and a spot
of colour for the number of zeros to give the value in μF.
然而，过去的钽电容是利用色码系统表示电容值大小的，这种色码系统由两个色带（代表两个数字）和表示零的数量的点组成，电容的单位是μF。 ones 表示前句中的tantalum bead capacitors。 6. Practically, there are free electrons in every dielectric due in part to impurities in the dielectric. 实际上，由于电介质中存在杂质，使得每种电介质中都有自由电子存在。
7. This in fact is the resistance of dielectric material through which leakage current flows.
电介质材料中有漏电流流过。Which 指句子中的dielectric material。
8. The response of a circuit to sudden application of a voltage or current is called “transient response”。
突然施加电压或电流的电路响应称为“暂态响应”。 9. Note that the existence of a closed circuit path drains the capacitor of its stored charge.
闭合电路消耗了电容中存储的能量。
10. Physically, the exponential decay shown in Figure 1.3 signifies that the energy stored in the
capacitor at t=0 is dissipated by the resistor at a rate determined by the product of the circuit
equivalent resistance（viewed from the capacitor）and the capacitance（R×C）.
实际上，图1.3 中的衰减指数表示从t=0 时刻开始，电容存储的能量以一定的速率被电阻消
耗，能量消耗的速率由电路的等效电阻和电容值决定。
句子中determined by the product of the circuit
equivalent resistance（viewed from the capacitor） and the capacitance（R×C）修饰rate。
11. Also note that where more sources and/or more resistors are involved, ETh and RTh, external to the capacitor, should be used in capacitor
1.3 Inductor
1. The material around which the coil is formed is called the “core”.
在其周围绕上线圈的材料称为铁心。
2. …from the instant transient starts to the time equal to about five time constants.
??从暂态起始时刻到大约5 倍时间常数的时刻。 3. A similar reasoning process explained for capacitor charging and discharging may be employed to
explain the behavior of an inductor when it is subjected to a sudden change in its current.
可以用电容充放电过程的类似地解释当电感电流突然变化时电感的行为。
1.4 Diode
1. Electricity uses up a little energy pushing its way through the diode, rather like a person pushing through a door with a spring.
电流消耗很少的能量就可以通过二极管，很像一个人推开带弹簧的门。
2. Without the diode no current could flow and the coil would produce a damaging high voltage
“spike” in its attempt to keep the current flowing. 如果没有二极管，就没有电流流动，线圈将产生一个很高的电压试图维持电流的流动。
3. Small signal diodes can be damaged by heat when soldering, but the risk is small unless you are
using a germanium diode（codes beginning OA...）in which case you should use a heat sink clipped to the lead between the joint and the diode body.
很少有信号二极管在焊接时因为过热而损坏，除非你正在使用锗二极管，若使用了锗二极管，就应该在二极管两个管脚之间连接一个散热器。 4. Rectifier diodes are quite robust and no special precautions are needed for soldering them.
由于整流二极管热适应性很强，因此焊接时不需要特别的防护。
5. They are designed to ?breakdown? in a reliable and
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non-destructive way so that they can be used in reverse to maintain a fixed voltage across their terminals.
稳压二极管能可靠地工作在击穿状态下，它们能反向使用从而在其两端产生一个固定的电压。 in reverse 反向。
6. If the calculated value is not available，choose the nearest standard resistor value which is greater,
so that the current will be a little less than you chose. 如果计算出的电阻值在标准的电阻系列里找不到，请选择最接近且比计算值大的标准电阻，这样电流就要小一些。
7. All the LEDs connected in series pass the same current so it is best if they are all the same type.
所有以串联方式相连的发光二极管都流过相同的电流，此时如果这些发光二极管型号相同，这种工作方式就是最佳的。
这里connected in series 是省略了that are 的从句，修饰the LEDs。
8. Connecting several LEDs in parallel with just one resistor shared between them is generally not a good idea.
几个并联连接的发光二极管仅与一个电阻相连接的工作方式通常不是一个好的工作方式。
Connecting several LEDs in parallel with just one resistor shared between them是主语，其中them
指several LEDs，shared between them 是省略了that is 的从句,修饰one resistor。
1.5 Transistors
1. Take care to include the 10k resistor in the base connection or you will destroy the transistor as you test it!
注意在基极端连接一个10 k 的电阻，否则当你测试时就会损坏三极管。
2.1 Resistance-Temperature Detectors
1. The two basic devices used are the
Resistance-Temperature Detector(RTD), based on the variation f metal resistance with temperature, and the thermistor, based on the variation of
semiconductor resistance with temperature.
使用的两个测温器件是电阻 — 温度检测器和热敏电阻，其中电阻 — 温度检测器的金属电阻随温度
变化而变化，热敏电阻的半导体电阻随温度变化而变化。
句子中的based on the variation f metal resistance with temperature 修饰the Resistance-
Temperature Detector, based on the variation of semiconductor resistance with temperature 修饰 the thermistor. the Resistance-Temperature Detector 和the thermistor 相并列。
2. A metal is assemblage of atoms in the solid state in which the individual atoms are in an
equilibrium position with superimposed vibration induced by the thermal energy.
金属在固体状态下由许多原子组成, 每个原子都处于平衡位置, 当这些原子受到热能作用时就会围绕这个平衡位置发生振动。
3. As the temperature is raised, the atoms vibrate with greater amplitude and frequency, which causes even more collision with electrons,?
随着温度的上升, 原子的振动幅度和频率逐渐变大, 这就加剧了原子与电子之间的碰撞，??
4. The use of either Equation(2.1), resistance versus temperature graphs, or resistance versus
temperature tables is practical only when high accuracy is desired.
实际应用时，要么使用公式(2.1)，即电阻—温度曲线，要么当期望高精度的测量结果时使用电阻—温度表格。
5. For many applications we can use an analytical approximation of the curves, for which we simply insert the temperature and quickly calculate the resistance,?
大多数情况下可以使用近似曲线，我们可以利用这个曲线由温度值迅速计算出电阻值，??
句子中which 指an analytical approximation of the curves。
6. Metals used in these devices vary from platinum, which is very repeatable, quite sensitive, and very expensive, to nickel, which is not quits as repeatable, more sensitive, and less expensive.
这些器件使用不同的金属制成，可以是重复性好、灵敏度高、价格高的白金，也可以是重复性不太好，但灵敏度更高、价格低的镍。
句中的which is very repeatable, quite sensitive, and very expensive 修饰platinum, which is not
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quits as repeatable, more sensitive, and less expensive 修饰nickel。
2.2 Thermistors
1. The particular semiconductor material used varies widely to accommodate temperature ranges, sensitivity, resistance ranges, and other factors.
使用的半导体材料变化范围很宽，从而使其能与温度的范围、灵敏度、电阻范围以及其他一些因素相适应。
vary 是不及物动词，“变化”之意。
2. at the low end 为“在测温范围的下限”之意。 3. Thus, for the smallest bead thermistors in an oil bath (good thermal contact), a response of 1/2s is typical. 因此，对于放在油中的最小的珠式热敏电阻，其典型的响应时间是1/2 秒。
4. The same thermistor in still air will respond with a typical response time of 10s.
同样的热敏电阻若放在静止的空气中, 它的典型响应时间是10 秒。
2.3 Thermocouples
1. This potential difference is related to the fact that electrons in the hotter end of the material have
more thermal energy than those in the cooler end, and thus tend to drift toward the cooler end.
材料热端的电子比冷端的电子具有更多的热能，因此热端的电子向冷端漂移从而产生电势差。
2. If a circuit is closed by connecting the ends through another conductor, a current is found to flow in the closed loop.
如果通过另一个导体将某材料的两端连接起来, 在闭合的电路中就有电流产生。
这里的circuit 指此句所在段落中提到的material。 3. We could not close the loop with the same metal because the potential differences across each leg would be the same,?
我们不能用相同的两个金属材料(图2.5 中金属A 与金属B 是相同材料)形成环路, 因为每个支路产生的电势差是相同的。句中的leg 译为“支路”，指本句中的metal,
4. the metals 指图2.5 中的金属A 与金属B。 5. Two other junctions then are formed to a common metal C, which then connects to measurement
apparatus.
金属A 和金属B 对于金属C 形成了另外两个接点，金属C 与测量仪器相连接。 句中的which 指metal C。
6. The voltage produced has a magnitude dependent on the absolute magnitude of the temperature difference and a polarity dependent on which temperature is larger, reference or measurement junction.
产生的电压的大小取决于温度差，产生的电压的极性取决于温度高的接点，要么是参考点， 要么是测量点。
7. A junction is formed with the measurement system, but to wires of the same type as the thermocouple.
8. 与热电偶类型相同的导线与测量系统连接形成接点。the tables 指热电偶分度表（电势差— 温度表）。
3.1 Analog Signal Conditioning
1. Signal conditioning refers to operations performed on signals to convert them to a form suitable for interfacing with other elements in the process-control loop.
信号调理是指对信号的处理，即将信号转换成一种适合与过程控制回路中其他单元接口的信 号。
2. Analog signal conditioning provides the operations necessary to transform a sensor output into a
form necessary to interface with other elements of the process-control loop.
模拟信号调理是把传感器输出转换成能与过程控制回路中其他单元接口的形式。 3. ?power will be dissipated by both. ??两个电阻都将消耗电能。
4. This means that amplification can be used to
increase the voltage level for increased sensitivity to variation of impedance.
为了增加对阻抗变化的灵敏度，使用放大电路增加电压值。
5. The values of a V and b V now can be found by noting that a V is just the supply voltage V divided between 1 R and 3 R .
a V 和 b V 的值能够得到, 因为电源电压V 在R1 与
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R3 上分压可得到R3 两端电压Va。
6. Equation (3.6) shows how the difference in potential 句子中的两个that 均指critical frequency。
16. One very special band-reject filter, which can be across the detector is a function of the supply voltage and the values of the resistors.
等式（3.6）表示侦测器两端电势差是电源电压和桥路电阻的函数。
7. ?the resistor values must satisfy the indicated equality.
??电阻值一定要满足等式。 equality 指文中的等式（3.7）。
8. This type of measurement is performed by placing the potential to be measured in series with the detector.，?
这种测量方法是通过将被测的电势与侦测器串联而实现的??
句中的to be measured 作为定语短语修饰the potential。
9. Note the nonlinearity of ?V with 4 R as it varies from 0 to 500 Ω.
当4 R 从0 到500 Ω变化时，?V 与4 R 成非线性关系。句中的it 指
10. Because of the ever-present ac power lines,? 由于交流电源线的存在，??
11. It would be most desirable if a low-pass filter had a characteristic such that all signals with
frequency above some critical value are simply rejected.
希望低通滤波器能阻止截止频率以上的信号。 句中with frequency above some critical value 用来修饰all signals。
12. ?by a power of the number cascaded. ??把级联滤波器的数量作为乘方。
13. Thus, two high-pass filters of the same critical frequency would respond by Equation (3.21) squared.
因此，两个具有相同截止频率的高通滤波器级联后的响应是等式（3.21）的平方。 14. load：把??作为负载
15. The lower critical frequency is that of the high-pass filter, whereas the high critical frequency is that of the low-pass filter.
（带通滤波器中）较低的那个截止频率是高通滤波器的截止频率，而较高的那个截止频率是 低通滤波器的截止频率。
realized with RC combinations, is called a notch filter because it blocks a very narrow range of frequencies.
由RC 组成的带通滤波器由于能阻止一个非常窄的频率范围的频率，因此称为槽型滤波器（也 称陷波滤波器）。 17. line：外型，轮廓
18. Resistor R2 is used to feed back the output to the inverting input of the op amp, and R1 connects the input voltage in V to this same point.
电阻R2 将输出信号反馈到放大器的反向输入端，电阻R1 在放大器的反向输入端与输入电 压
in V 相连接。this same point 指反向输入端。 19. plus and minus 指“±”。
20. An ideal differential amplifier is one that provides an output voltage with respect to ground that is some gain times the difference between two input voltages.
一个理想的差动放大器能提供一个输出电压，这个输出电压是两个输入电压之差的倍数。
句中的that is some gain times the difference between two input voltages 用来解释output voltage。 times 译为“倍数”。 21. provided：假设
3.2 Digital Signal Conditioning
1. Computers are digital electronic devices and so all the information they work with has to be digitally formatted.
计算机是数字电子装置，因此它所处理的信息必须是数字化的信息。
2. Although not as commonly used, it is possible to define a fractional binary number in the same
manner as whole numbers using only the 1 and 0 of this counting system.
在只有0 和1 的计数系统中，虽然分数不太常用，但是以与整数同样的方式定义一个分数 二进制数是可能的。
3. Before a particular problem in industry can be addressed using digital electronics, it must be analyzed in terms that are amenable to the binary
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nature of digital techniques.
在使用数字电子技术解决工业上的特殊问题前，必须先根据数字技术的二进制特性分析这些问题。 are amenable to：服从。
4. tri-state 指 tri-state buffer，即“三态缓冲器”。 以10 为基数的数，即十进制数。
12. When a logic command is given to latch data, whatever data are on the input bus will be latched
into the DAC and the analog output will be updated for that input data.
5. vice versa
反过来也一样。
6. Most measurements of process variables are
performed by devices that translate information about the variable to an analog electrical signal.
过程变量的测量可通过一个装置来实现，这个装置能将与变量有关的信号转换成一个模拟电信号。 句中的that translate information about the variable to an analog electrical signal 修饰devices.
7. One of the voltages on the comparator inputs, Va or Vb in Figure 3.35, will be the variable input,
and the other a fixed value called a trip，trigger, or reference value is computed from the
specifications of the problem and then applied to the appropriate comparator input terminal.
比较器输入端的电压之一即图3.35 中的Va 或 Vb 是变量输入，另一个输入是固定值，称为触发器或参考值，这个值根据所求得的问题计算出来，然后将其输入到电压比较器的一个输入端。
句中a fixed value 用来解释the other； called a trip，trigger, or reference value 是省略了that is的定语从句, 修饰the other。 8. power 给??供电。
9. The comparator output may “jiggle” back and forth between high and low as the reference level is reached.
当输入电压值达到参考电压值时，比较器的输出会在高/低电平之间来回跳变。
10. A unipolar DAC converts a digital word into an analog voltage by scaling the analog output to be zero when all bits are zero and some maximum value when all bits are one.
单极性DAC 通过按比例配置模拟输出将数字量转换成模拟电压，当所有数字量均为0 时，
模拟电压是0，当所有数字量是1 时，模拟电压取最大值。
scaling：按比例配置。 11. base 10
当发出锁存数据命令时，在输入总线上的任何数据都将被锁存到DAC 中，并且模拟输出量将随输入数据而更新。句中的are on the input bus 是省略了that 的从句，修饰data。
13. The existence of a finite conversion time complicates the use of ADCs in data acquisition. 有限的转换时间的存在使得使用ADC 进行数据采集时变得复杂。
14. This A/D converter employs a feedback system to perform the conversion, as shown in Figure 3.43. 这种A/D 转换器使用一个反馈系统实现转换，如图3.43 所示。employs：使用。
16. When the electronic switch is closed the capacitor voltage will “track” the input voltage,
VC (t) Vin (t) ??.
当电子开关闭合时，电容电压将随输入电压而变化，即VC (t) Vin (t) ??。track：跟随。
17. Whenever an SC is issued to the ADC, a “hold” is also issued to the S/H circuit.
当向ADC 发出SC（启动转换）信号时，同时向S/H（采样/保持）电路发出保持信号。
18. An as yet not identified device converts the sensor signal into a proportional frequency, s f .
一个尚未归类的器件能将传感器输出信号转换成与频率
s f 成比例的信号。
as yet：至今，迄今，常用在否定句中。
19. The counter often has a latch on the output that allows the counter to be accumulating a new count of input frequency while still maintaining the previous output.
计数器的输出锁存器允许计数器在前一输出的基础上进行累加计数。
3.3 Structure of Data Acquisition Systems
1. Microprocessor-based personal computers (PCs) are extensively used to implement direct digital
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