電導(dǎo)的定義及計(jì)算公式和電導(dǎo)單位與電路圖符號

Definition and calculation formula of conductance and conductance unit and circuit diagram symbol

前一課程中我們學(xué)習(xí)過《什么是電阻？電阻的作用及電阻計(jì)算公式及單位換算介紹》，我們知道導(dǎo)體對電流的阻礙作用稱為電阻，而什么是電導(dǎo)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?

導(dǎo)體的電阻越大，其導(dǎo)電性能就越差，反之電阻越小，導(dǎo)電性能就越好。因此電阻R的倒數(shù)電阻的倒數(shù)是電導(dǎo)的大小表面了導(dǎo)體導(dǎo)電性能的好壞，所以電導(dǎo)是表示一個物體或電路，從某一點(diǎn)到另外一點(diǎn)，傳輸電流能力強(qiáng)弱的一種測量值，其大小與物體的電導(dǎo)率和幾何形狀和尺寸有關(guān)。在電工學(xué)中，以電導(dǎo)表示物體傳導(dǎo)電流的本領(lǐng)，其符號用大寫字母“G”表示。所以電導(dǎo)的計(jì)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:

電導(dǎo)計(jì)算公式

Conductivity calculation formula

電導(dǎo)的單位是“西門子（S）”或者姆歐（電導(dǎo)單位：姆歐）。類似的，電阻率ρ（念作“rou”）的倒數(shù)成為電導(dǎo)率，用它通常由希臘字母σ（西格瑪），但κ（卡伯）（特別是在我們電工電氣工程中），偶爾也使用γ（伽馬）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.

電阻和電導(dǎo)在電路中中使用以下簡要符號來表示：

Resistance and conductance are represented in circuits by the following brief symbols:

電阻、電導(dǎo)符號

Resistance and conductance symbols

順便指出：金屬從溫室開始冷卻，金屬的電阻率隨之下降（眾所周知很多金屬的電阻會隨溫度而變化的，電導(dǎo)率依然），而且溫度越低，電阻率也越小（絕大部分是如此），某些導(dǎo)體具有某個臨界溫度，當(dāng)臨界溫度是導(dǎo)體的電阻幾乎等于0，這種情況下導(dǎo)體變成“超導(dǎo)”了。在電力工程中，將低溫技術(shù)用于創(chuàng)造有利于超導(dǎo)的條件，將使設(shè)備的尺寸有可能大大減小（知道問什么嗎？聰明的讀者一定知道）。

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 電機(jī)引接線 金湖縣春晨 電機(jī)引接線 金湖縣春晨 電機(jī)引接線 金湖縣春晨 電機(jī)引接線 金湖縣