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“导体中的电流,跟导体两端的电压成正比,跟导体的电阻成反比.”写成公式就是I=U R.这就是著名的欧姆定律.公式的物理意义是:当导体的电阻R一定时,导体两端的电压增加几倍,通过这段导体的电流就增加几倍.这反映导体的电阻一定时,导体中的电流跟导体两端的电压成正比.当电压一定时,导体的电阻增加到原来的几倍,则导体中的电流就减小为原来的几分之几,这也反映了电压一定时,导体中的电流跟导体的电阻成反比.对欧姆定律的理解,应注意以下三个方面:1欧姆定律中的电流、电压和电阻这三个量是对同一段导体、同一时刻而言的.2对于一段电路,只要知道I、U、R三个物理量中的任意两个,就可应用欧姆
“The current in the conductor, which is proportional to the voltage across the conductor, is inversely proportional to the resistance of the conductor.” Writing the formula is I = U R. This is the well-known Ohm’s law. The physical meaning of a formula is that when the resistance R Certainly, the voltage across the conductor increases several times, the current through this section of the conductor to increase several times.This reflects the conductor resistance, the conductor current with the voltage across the conductor is proportional to.When the voltage is constant, the resistance of the conductor To several times the original, then the current in the conductor is reduced to a fraction of the original, which also reflects the voltage at a certain time, the conductor current is inversely proportional to the resistance of the conductor. Understanding of Ohm’s law, should pay attention to The following three aspects: 1 Ohm’s law in the current, voltage and resistance of these three quantities is the same piece of conductor, at the same time.2 For a circuit, as long as know I, U, R three physical quantities of any two A, ohm can be applied