正弦交流电的分析
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这便引出通常所说的均方根（或有效值）电流的 概念，其定义如下：(Eq.1)
在dt时间里电流i通过电阻r产生的热量为(Eq.)
.
It follows that the r.m.s. (effective) value of an alternating current is numerically equal to the magnitude of the steady direct current that would produce the same heating effect in the same resistance and over the same period of time.
两载流导体之间的作用力与导体中的电流的平方成正比 。某段时间内电流通过一个电阻所产生的热量也正比于 电流的平方。
New Words & Expressions:
sinusoidal alternating electricity 正弦交流电 effective values 有效值 r.m.s. values = root mean square values 均方根值 square平方
.
This calls for knowledge of what is known as the root mean square (or effective) current defined as (Eq.1)
The heat developed by a current i in a resistance r in time dt is (Eq.)
Let there be a sinusoidal time function (current, voltage, magnetic flux and the like):
如果所涉及的正弦量用矢量和复数表示，便可大大地简化交流电 路的分析。
设一正弦时间函数（电流、电压、磁通等）
New Words & Expressions:
在涉及交流电压和电流时，通常指的值就是其 均方根（有效）值，同时将限定词“均方根（ 有效）”几个字略去，并不明指。
.
Representation of Sinusoidal Time Functions by Vectors and Complex Number正弦时间函数的矢量和复数表示法
A.C. circuit analysis can be greatly simplified if the sinusoidal quantities involved are represented by vectors or complex numbers.
Hence :(Eq.2)
The r.m.s. (effective) values of e.m.f. and voltage are
ห้องสมุดไป่ตู้
New Words & Expressions:
peak values 峰值
.
In dealing with periodic voltages and currents, their r.m.s. (effective) value are usually meant, and the adjective “r.m.s.” or “effective” is simply implied.
Unit4 Analysis of Sinusoidal Alternating Electricity
——正弦交流电的分析
.
R.M.S. (Effective) Values of Current and Voltage——电压和电流的有效值
The force between two current-carrying conductors is proportional to the square of the current in the conductors. The heat due to a current in a resistance over a period is also proportional to the square of that current.
句型It follows that …译为“由此得出…”。宾 语从句里面含有一个定语从句。
由此可得出，交流电的均方根（或有效）值等于 在相同电阻、相同时间内产生相同热量的恒稳直 流电的大小。
New Words & Expressions:
steady direct current 恒稳直流电
.
Let us establish the relationship between the r.m.s. and peak values of a sinusoidal current, I and Im
矢量 magnetic flux磁通
It can be represented in vector form as follows. Using a righthand set of Cartesian coordinates MON (Fig.1), we draw the vetor Vm to some convenient scale such that it represents the peak value Vm and makes the angle φ with the horizontal axis OM (positive values of φ are laid off counter-clockwise, and negative, clockwise).
sinusoidal time function正弦时间函数
vector
complex number 复数 sinusoidal quantity 正弦量
A.C. circuit=alternating current circuit 交流电路
D.C. circuit=direct current circuit 直流电路
在dt时间里电流i通过电阻r产生的热量为(Eq.)
.
It follows that the r.m.s. (effective) value of an alternating current is numerically equal to the magnitude of the steady direct current that would produce the same heating effect in the same resistance and over the same period of time.
两载流导体之间的作用力与导体中的电流的平方成正比 。某段时间内电流通过一个电阻所产生的热量也正比于 电流的平方。
New Words & Expressions:
sinusoidal alternating electricity 正弦交流电 effective values 有效值 r.m.s. values = root mean square values 均方根值 square平方
.
This calls for knowledge of what is known as the root mean square (or effective) current defined as (Eq.1)
The heat developed by a current i in a resistance r in time dt is (Eq.)
Let there be a sinusoidal time function (current, voltage, magnetic flux and the like):
如果所涉及的正弦量用矢量和复数表示，便可大大地简化交流电 路的分析。
设一正弦时间函数（电流、电压、磁通等）
New Words & Expressions:
在涉及交流电压和电流时，通常指的值就是其 均方根（有效）值，同时将限定词“均方根（ 有效）”几个字略去，并不明指。
.
Representation of Sinusoidal Time Functions by Vectors and Complex Number正弦时间函数的矢量和复数表示法
A.C. circuit analysis can be greatly simplified if the sinusoidal quantities involved are represented by vectors or complex numbers.
Hence :(Eq.2)
The r.m.s. (effective) values of e.m.f. and voltage are
ห้องสมุดไป่ตู้
New Words & Expressions:
peak values 峰值
.
In dealing with periodic voltages and currents, their r.m.s. (effective) value are usually meant, and the adjective “r.m.s.” or “effective” is simply implied.
Unit4 Analysis of Sinusoidal Alternating Electricity
——正弦交流电的分析
.
R.M.S. (Effective) Values of Current and Voltage——电压和电流的有效值
The force between two current-carrying conductors is proportional to the square of the current in the conductors. The heat due to a current in a resistance over a period is also proportional to the square of that current.
句型It follows that …译为“由此得出…”。宾 语从句里面含有一个定语从句。
由此可得出，交流电的均方根（或有效）值等于 在相同电阻、相同时间内产生相同热量的恒稳直 流电的大小。
New Words & Expressions:
steady direct current 恒稳直流电
.
Let us establish the relationship between the r.m.s. and peak values of a sinusoidal current, I and Im
矢量 magnetic flux磁通
It can be represented in vector form as follows. Using a righthand set of Cartesian coordinates MON (Fig.1), we draw the vetor Vm to some convenient scale such that it represents the peak value Vm and makes the angle φ with the horizontal axis OM (positive values of φ are laid off counter-clockwise, and negative, clockwise).
sinusoidal time function正弦时间函数
vector
complex number 复数 sinusoidal quantity 正弦量
A.C. circuit=alternating current circuit 交流电路
D.C. circuit=direct current circuit 直流电路