电导的定义及计算公式和电导单位与电路图符号
Definition and calculation formula of conductance and conductance unit and circuit diagram symbol
前一课程中我们学习过《什么是电阻？电阻的作用及电阻计算公式及单位换算介绍》，我们知道导体对电流的阻碍作用称为电阻，而什么是电导呢？
In the previous lesson, we learned "What is resistance?" The function of resistance and the formula of resistance calculation and unit conversion. We know that the obstruction of conductor to current is called resistance. What is conductance?
导体的电阻越大，其导电性能就越差，反之电阻越小，导电性能就越好。因此电阻R的倒数电阻的倒数是电导的大小表面了导体导电性能的好坏，所以电导是表示一个物体或电路，从某一点到另外一点，传输电流能力强弱的一种测量值，其大小与物体的电导率和几何形状和尺寸有关。在电工学中，以电导表示物体传导电流的本领，其符号用大写字母“G”表示。所以电导的计算公式是：
The larger the resistance of a conductor, the worse its conductivity. On the contrary, the smaller the resistance, the better its conductivity. Therefore, the reciprocal resistance of resistance R is the surface of conductivity, which indicates the conductivity of a conductor. Therefore, conductivity is a measure of the transmission current capacity of an object or circuit from one point to another. Its size is related to the conductivity and geometric shape and size of the object. In electrotechnics, the ability of conducting current of an object is expressed by conductance, and its symbols are expressed by capital letter "G". So the formula for calculating conductance is:
电导计算公式
Conductivity calculation formula
电导的单位是“西门子（S）”或者姆欧（电导单位：姆欧）。类似的，电阻率ρ（念作“rou”）的倒数成为电导率，用它通常由希腊字母σ（西格玛），但κ（卡伯）（特别是在我们电工电气工程中），偶尔也使用γ（伽马）表示。
The unit of conductivity is "Siemens (S)" or MO (unit of conductivity: MO). Similarly, the reciprocal of resistivity Rho (pronounced "rou") becomes conductivity, which is usually expressed by the Greek letter_ (sigma), but kappa (kappa) (especially in our electrical and electrical engineering) is occasionally expressed by gamma.
电阻和电导在电路中中使用以下简要符号来表示：
Resistance and conductance are represented in circuits by the following brief symbols:
电阻、电导符号
Resistance and conductance symbols
顺便指出：金属从温室开始冷却，金属的电阻率随之下降（众所周知很多金属的电阻会随温度而变化的，电导率依然），而且温度越低，电阻率也越小（绝大部分是如此），某些导体具有某个临界温度，当临界温度是导体的电阻几乎等于0，这种情况下导体变成“超导”了。在电力工程中，将低温技术用于创造有利于超导的条件，将使设备的尺寸有可能大大减小（知道问什么吗？聪明的读者一定知道）。
Incidentally, when metals begin to cool down in greenhouses, the resistivity of metals decreases (it is well known that the resistance of many metals varies with temperature and the conductivity remains unchanged), and the lower the temperature, the smaller the resistivity (mostly so). Certain conductors have a critical temperature, and when the temperature is below the critical temperature, they are conductors. The resistance is almost equal to zero, in which case the conductor becomes "superconducting". In power engineering, the use of cryogenic technology to create conditions conducive to superconductivity will make it possible to greatly reduce the size of the equipment (do you know what to ask? Smart readers must know.春晨 电机引接线 金湖县春晨 电机引接线 金湖县春晨 电机引接线 金湖县春晨 电机引接线 金湖县
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