导图社区 电工及电子技术基础Electrical and Elect
交流电i和直流电I分别流过阻值相同的电阻,如果在一个周期内它们所产生的热量相等,即其热效应相等,就称该直流电的数值是交流电的有效值。
编辑于2021-12-25 19:01:50电工及电子技术基础 Electrical and Electronic Technology Base
基本概念与定理 Basic concepts and theorems
电路 circuit
基本组成 basic component
电源 power supply
负载 load
中间环节 middle term
工作状态 Working status
通路 closed circuit
开路 open circuit
短路 Short circuit
常见理想电路元件 Common ideal circuit components
电阻元件 Resistance element
电感元件 Inductance element
电容元件 Capacitive element
电源元件 Power components
理想电压源 ideal voltage source
理想电流源 ideal current source
基本物理量 Basic physical quantity
电流 Current
电压 Voltage
电功率 Electric power
基尔霍夫定律 Kirchhoff's Law
常用的名词 Frequently used nouns
支路 Branch road
结点 Node
回路 Loop
网孔 Mesh
基尔霍夫电流定律 KCL Kirchhoff's current law
在任一瞬间,流入结点的电流之和必定等于流出该结点的电流之和 At any instant, the sum of currents flowing into a node must be equal to the sum of currents flowing out of that node
基尔霍夫电压定律 KVL Kirchhoff's voltage law
电路中任一回路,在任一瞬间,沿回路绕行方向,各段电压升降之和为零 Any loop in the circuit, at any instant, along the detour direction of the loop, the sum of the voltage rise and fall of each section is zero
直流电阻性电路 DC resistive circuit
串并联电阻特性等
电源等效变换 Equivalent conversion of power supply
理想电源等效变换
实际电源等效变换
支路电流法 Branch current method
是分析复杂电路的基本方法(复杂电路:包含多个回路的电路)
基于基尔霍夫定律
列出与支路个数相同的方程构成方程组,然后联立求解
叠加定理 Superposition theorem
当线性电路中有多个电源时,任一支路的电流或电压可以看作是各个电源单独作用时产生的电流或电压代数和 When there are multiple power supplies in a linear circuit, the current or voltage of any branch can be regarded as the algebraic sum of the current or voltage generated by each power supply alone.
三相交流电 Three-phase alternating current
三相交流电源是三个单相交流电源按一定方式进行的组合,它们之间满足幅值相等、频率相同、相位相差120°的关系 Three-phase AC power supply is a combination of three single-phase AC power supplies in a certain way, and they meet the relationship of equal amplitude, same frequency, and 120° phase difference.
优点
体积小、成本低 Small size and low cost
使用及维护方便,运转时振动小 Easy to use and maintain, low vibration during operation
结构简单、性能好、运行平稳可靠、旋转力矩大 Simple structure, good performance, stable and reliable operation, large rotating torque
与单相交流发电机相比 Compared with single-phase alternator
排列方式
星形联结 star connection
相电压 phase voltage
三相电源中任意一根相线与中性线之间的电压 The voltage between any phase line and neutral line in the three-phase power supply
线电压 line voltage
三相电源任意两根相线之间的电压 The voltage between any two phase wires of a three-phase power supply
三角形联结 Triangle connection
因为没有中线,所以对外只能提供一种电压,即线电压 Because there is no neutral line, only one voltage can be provided externally, that is, the line voltage
其负载必须为对称负载 The load must be a symmetrical load
正弦交流电 Sinusoidal alternating current
电流的大小和方向随时间做周期性变化(正弦) The magnitude and direction of the current change periodically with time (sinusoidal)
广泛使用原因
交流电容易产生、转化和传输 Alternating current is easy to generate, transform and transmit
转化为直流电容易 Easy to convert to direct current
正弦周期函数是最简单的周期函数 The sine periodic function is the simplest periodic function
三要素
变化快慢 Change fast
周期 cycleT
频率f frequency
角频率w Angular frequency
相位 Phase
初相位 Initial phase
相位差 Phase difference
电量大小 Current
瞬时值 Instantaneous value
最大值 Max
有效值 Effective value
交流电i和直流电I分别流过阻值相同的电阻,如果在一个周期内它们所产生的热量相等,即其热效应相等,就称该直流电的数值是交流电的有效值
计算公式