大纲
交流波介绍
交替的电流是定期改变其方向的那些。由于我们置于较早的AC电流本质上是BI定向的。AC波形是代表 /描述交替电流的所有字符的波形。
Generally we will represent AC waveform by Sinusoidal waveform and its mathematical formulae is
a（t）= a sin（2πƒt）
在哪里 ，
a是信号的振幅
T是时间段
F是信号的频率
在产生交流电流的过程中，将电线或线圈旋转在由2个磁体产生的磁场中。如果我们绘制移动线圈 /线相对于时间的实例，它将形成一个称为“ AC波形”的交替电流图。交替的电流波形随时间而变化，因此它们也被称为时间依赖信号或周期信号。
基于AC电流的生成方法，我们将获得不同类型的波形。但是正弦波形是描述交流电流的最常用波形。
交流波形表示
借助正弦波形，我们可以理解交流电流的所有特征和演变。我们代表正弦波相对于其时间段的幅度。幅度（或有时称为电压）以垂直轴表示，水平轴代表时间段。
在AC波形表达中，A（T）= A SIN（2πƒT），A（T）是随时间而变化的函数。通常，AC波形将如下所示。
AC波形在正半周期和负半周期中具有相同的幅度。波形的幅度将相对于时间测量。这就是为什么AC波形取决于时间的原因。
定期波形的类型
There are many types of wave forms with which we can explain the alternating current. As the AC current is time dependent i.e. periodic, all the wave forms which are use to describe the AC current are also periodic. The other types of wave forms that are commonly used to represent the AC current are stated below.
- 正弦波
- Square wave
- Saw – tooth wave
- 三角波
由于我们已经熟悉正弦波，让我们从方波形式开始。
1. Square Waveform
方波形式主要用于表示电路，例如电路电路输出和时钟信号表示。这些本质上是对称的，这意味着它们代表正和负波形的同等持续时间。
这些波形不舍入。它们没有达到峰值幅度，而是在峰值电压水平的垂直上下垂直下来。由于平坦的顶部，它们看起来像方形。这就是为什么它们被称为“方波形”。方波的示例如下图所示
We already learn that the square wave forms are symmetrical in nature. In this, the time taken to complete the positive half cycle must be equal to the time taken to complete the negative half cycle. So that we can calculate the duty cycle of the square wave by calculating the rise time and fall times. The Duty cycle means “The time taken for the positive half cycle by the to the wave form”.
If we say the time taken for the + ve half cycle is “On time” and the time taken for the – ve half cycle is “Off time”. The frequency of the square wave form can be found by the given formula.
频率= 1/（“ on”时间+“ off”时间）
大部分的数字电子电路波形are represented in square wave forms only.
2. SAW – TOOTH Waveform
This is another type of periodic wave form. In this wave form the peaks of the wave-form at extreme times (low or high) are like teeth of Hack-saw blade. That’s why we call this as Saw-tooth wave form. Saw tooth wave forms are of two types. One is positive ramp saw-tooth wave and other is negative ramp saw-tooth wave form.
In the positive ramp saw tooth wave, it has slow rising time and high steep decay.
在负坡道锯齿波中，它的时间很快，并且陡峭的衰减较慢。
最常用的齿牙波形是正斜向波。它具有偶数谐波的频率，例如1/2、1/4、1/6 1/8…1/N等。
The saw tooth wave form is used by musicians to produce the high clarity sound in audio devices, because of its high harmonic capacity.
3.三角波
三角波s are those which will oscillate between positive and negative values. These are also bi directional in nature. Its shape is similar to that of linear positive ramp saw tooth wave form. The triangular waves have slow rising time and sloe decaying times.
三角波形式中电压的变化速率在其正和负半周期中相等。
The triangular wave forms have their duty cycle as 50%, since it takes equal time to rise and fall down. The frequency of the triangular wave is the average of its voltage level.
交流波形特征
交流波形可以用其基本关键特征（例如振幅，频率，时间段）来解释。
1.振幅
电流或电压的最大值称为“振幅”。这由正弦波的正峰或负峰值表示。该最大电压水平也被认为是峰值电压。它可能是正面或负面的。值中的负符号指示电流流的方向。
2. Time Period
The time taken to complete one full cycle is known as “Time period”. It is denoted as ‘T’. The time period can be calculated, starting from any point on the AC sine wave. No matter where we start measuring the time period, it is the matter of completing one full cycle.
3.频率
The frequency of a wave form is the reciprocal of its time period. It can also be explained as “The number of times that sine wave cycle occurs in a second”. Frequency is measured in HERTZ, by the name of a German scientist Henrich Hertz, who proved the existence of electromagnetic waves.
它由字母“ f”代表
频率可以通过以下给定公式来测量。
Frequency = 1 / Time Period.
Summary
- 定期更改其方向的电流称为“交流电流”或“交流电流”。
- 代表交流波形特征的波形称为“交流波形”。
- 通常，我们使用正弦波来解释交流电流特征。
- 我们可以使用许多其他类型的波形形式来解释交流电流。他们是
- 方波形式
- 三角波形
- Saw – tooth wave form
- 交流波形式的基本特征是振幅，时间段和频率。
