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作者:高考题库网
来源:https://www.bjmy2z.cn/gaokao
2021-03-02 21:39
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2021年3月2日发(作者:时机)



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bypass [ 'bai.p


ɑ


:s ] n.


支路,道



coil [ k


?


il ] n.


卷,线圈



discharge [ dis?t


?


ɑ


:d

< br>?



] v


. & n.


放电



filter [ ?filt?


] n.


滤波器,过滤器



v.


过滤



heatsink [ hi:t si?k ] n.


散热器



magnetic [ m?g'netik ] a.


磁的



mains [ mein ] n.


电网



outlet [?autlet] n.


电源插座



passive [ 'p?siv ] a.


被动的


,


消极的;无源的



Pulse


Rate


Modulated


(PRM)


Regulator


脉冲


速率调节器



RMS (=Root-Mean-Square)


均方根




?



?



?



?



?



?



?



?



?



?



?



pulsating [ 'p


?


ls


?ti?]a.


脉动的



rated [ 'reitid ] a.


标称的



ripple [ ?ripl ] n.


纹波



sample [ 's?mpl]n.


样品;标本


v


.


抽取样品



smooth [ smu:?


] a.


平稳的,


流畅的



v.


使


...


光滑,


滤波



transformer [tr?ns'f


?


:m


?


(r), tr


ɑ


:- ] n.


变压器



bridge rectifier


桥式整流器



magnetic field .


磁场



overheating


过热



Pulse


Width


Modulated


(PWM)


Regulator


脉冲


宽调制调节器




When working with electronics, you always need power supply, a device that transfers electric power from a source


to a load using electronic circuits.


翻译:当你工作中用到电子学时你就需要电源装置。电源是一用电路把电能从电


源输送给负载的设备。



A typical application of power supplies is to convert utility's AC input power into regulated DC voltage(s) required


for electronic equipment. Depending on the mode of operation of power semiconductors power supply can be linear


or


switching.



电源的主要用途是将有效的交流输入功率转换为电子设备所需的直流电压。根据电源功率半导体 器


件的工作方式电源装置可以是线性或开关式的。



Linear


voltage


power


supplies


are


commonly


used


for


both


step-up


(output supply


voltage


is


greater


than


inp


ut


source voltage) and step-down (output supply voltage is lower than input source voltage) applications. Linear power


supplies


are


also


available


with


either


a


fixed


output


voltage


or


a


variable


output


voltage


when


using


external


biasing


.


< br>:


线性稳压器常用于电压的提升


(输出供电电压大于输入 源电压)


和降低


(输出供电电压低于输入源电压)



使用外部偏置,线性稳压器也可产生恒定输出电压或可变输出电压。



The basic block of a linear power supply is shown in Figure 2-1, which includes: T


ransformer, which steps down


high


voltage


AC


mains


to


low


voltage


AC;


Rectifier,


which


converts


AC


to


DC,


but


the


DC


output


is


varying;


Filtering, which filters the DC from varying greatly to a small ripple; Regulator


, which eliminates ripple by setting


DC output to a fixed voltage.



线性电源可以分解为一系列基本模块,如图


2-1


所示,该图包括:变压器


——< /p>


把电网


高压交流电转换为低压交流电;整流器

——


把交流电转换为直流电,但是直流输出是变化的;滤波器


——


从直流


电流中滤掉变化较大的成分使之仅有小的纹波成分 ;稳压器


——


消除纹波,输出固定值的直流电压



Transformer converts the voltage from the wall outlet (mains) to a different, usually a lower voltage. The input coil


is called the primary and the output coil is called the secondary. There is no electrical connection between the two


coils; instead they are linked by an alternating magnetic field created in the soft- iron core of the transformer.


当一


个小的电压


V


正向加到二极管 时,就会有一个小的电流流过,并产生一个大约为


0.6V


到< /p>


1V


的电压降


V


on


,这常


被认为是二极管的“正向电压降”

< br>,若为硅二极管,大约为


0.7V




Bridge rectifiers are rated by the passed maximum current and the maximum reverse voltage they can withstand


(this must be at least three times the supply RMS voltage so the rectifier can withstand the peak voltages).


桥式整


流器是由它能 通过的最大电流值和所能承受的最大反向电压(这一电压值至少是均方根电压的三倍,这样整流器


才能承受住峰值电压)来标称的。








A


filter


,


consisted


of


capacitors


or


resistors


or


inducers


or


their


combinations,


is


used


to filter


part


of


the


pulses


giving a smoothed DC voltage. However, filtering is not perfect and small pulses, known as ripple, are still remained.


For many circuits a ripple, which is 10% of the supply voltage, is satisfactory.


由电容器,或电阻器,


或电感器,


< br>它们的组合而构成的滤波器可过滤部分脉冲而得到平滑的直流电压。然而,滤波器不是完美的,仍然存在小 脉冲,



常称之为纹波电压。对于许多电路来说,纹波电压大小 为电源电压的


10


%是合适的。



A simple voltage regulator for low current power supplies can be made up of a resistor and a Zener diode connected


in reverse. But nowadays, many types of voltage regulator ICs can be available with fixed


(typically 5, 12 and 15V)


or


variable


output


voltages,


largely


simplifying


the


regulator


designs.


Most


regulators


include


some


automatic


protection from excessive current (?overload protection?) and overheating (?thermal protection?).


用于低电流电源,


稳压器可以简 单地由一个电阻和一个反向连接的齐纳二极管构成。但是目前,许多类型的集成稳压器的输出可以


为固定值(通常为


5


伏,


12


伏和


15


伏)或可变值,大大简化了设 计过程。大部分稳压器都具有一些过电流


(


过载


保护


)


和过热(热保护)自动保护功能



Many


of


the


fixed


voltage


regulator


ICs


has


3


leads


and



look


like


power


transistors,


such


as


the


7805


+5V


1A


regulator. They include a hole for attaching a heatsink if ne cessary.


:许多固定输出的集成稳压器有


3

< p>
根引线,看




起来像功率晶体管,例如


7805+5V 1A


稳压器。它们包含一个孔,如果必要的话,在此孔上可以附加一个散热片。





The


advantage


of


linear


regulators is


simple


implementation


and


minimal


parts


(just the IC


in


the


case


of


fixed


output) and low output ripple. The major disadvantage of linear regulators is low efficiency.


线性稳压器的优点是< /p>


实现简单、部件体积小(就固定输出而言恰好是集成电路)和输出纹波低。线性稳压器的主 要缺点是效率低。



Switch mode power supply are continuously switching on and off with high frequency from 20 kHz to several MHz


to provide the transfer of electric power via energy storage components (inductors and capacitors).



开关式电源装



置连续不断地以


20


千赫至几兆赫的高频率进行开关操作通过储能元件(电感器和电容器)提供电能的转换。




A basic switch mode power supply is consisted of a rectifier, a switching transistor, a step up/down



transformer, and


a


switching


controller--Pulse


Width


Modulated


(PWM)


Regulator


or


Pulse


Rate


Modulated


(PRM)


Regulator


,


a


high speed switching diode, and a capacitor, as shown in Figure 2-2, in which the heart is the switching transistor


and switching transformer.


一套基本的开关式电源由一个整流器 、一个开关晶体管、一个升压


/


降压变压器、一个



开关控制


-


脉冲宽度调制 (


PWM


)调节器或脉冲速率调制(


P RM


)调节器、一个高速开关二极管和一个电容器组


成。如图< /p>


2 -2


所示,其中核心器件是开关晶体管和开关变压器。



By


controlling


the


amount


of


“on


time”


and


“off


time”


of


the


switches,


the


amount


of


power


delivered


to


the


transformer?s load can



be controlled. PWM regulators vary the “on” or conduction time of the switching transistor,


while the PRM regulator varies the modulation rate (frequency) at which the switching transistor is turned off and


on, and these regulations are achieved by sampling the DC output voltage and comparing it to a reference voltage.


控制开关的打开时间和关闭时间的 总数,


可以控制传递到变压器负载上的电量。


PWM

< p>
改变开关晶体管打开或导通


的时间,而


PRM


改变调制速率,此调制速率是开关晶体管关闭和开启的速率(频率)


,这些调节是把采样到的直


流输出电压和参考电压相比而达到的





As


the


transistor


is switched


on


and


off


the


magnetic


field


alternately


expands


and


collapses in


the


transformer


windings.


By


designing


the


transformer


with


different


secondary


turn?s


ratios,


various


amplitude


pulses


are


produced at the output of each secondary winding. The output of each winding is applied to high speed swi


tching


diodes and filters (capacitors or inducers) which produce the DC output voltages of the switch mode power supply.




随着晶体管的打开和关闭,变压器绕组中的磁场交替增强和减 弱。用设计具有不同的次级匝数比的变压器,就会


在每个次级绕组的输出端产生不同的幅 度脉冲。每个绕组的输出端连接到高速开关二极管和滤波器(电容器或电


感器)上,以产 生出开关式电源的直流输出电压。



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