EMF vs Voltage
Both voltage and EMF (electromotive force) describe the electrical potential difference, but are different terms. The term ‘voltage’ has a common use, and it is same as the electrical potential difference. But, EMF is a specific term and used to describe a voltage generated by a battery.
Voltage
Voltage is another word for electrical potential difference. Potential difference between point A and B is also known as the voltage between point A and point B. It is also defined as the amount work to be done to move a unit charge (+1 Coulomb) from B to A. Voltage is measured in the unit Volts (V). Voltmeter is the equipment used to measure voltage. A battery provides a voltage between its two ends (electrodes) and its positive side has a higher potential and negative has a lower potential.
In a circuit, current flows from the higher potential to lower potential. When it goes through a resister, a voltage between two ends can be observed. This is called as a ‘voltage drop’. Although the voltage is always about two points sometimes people ask for a voltage of a point. This is about the voltage between that particular point and a reference point. This reference point is usually ‘grounded’ and potential of it is considered as 0V.
EMF (ElectroMotive Force)
EMF是电池等能源提供的电压。不同的磁场也可以根据法拉第定律产生EMF。尽管电动势也是电压，并且在伏特（V）中测量，但这全都与电压产生有关。EMF对于电子电路驱动电流通过电路至关重要。它的行为喜欢充电泵。
When a electric circuit is run using an EMF, the sum of the voltage drops in that circuit equals to the EMF according to the Kirchhoff’s second law. In addition to the batteries, which use electrochemical energies, solar cells, fuel cells and thermocouples are also examples for EMF generators.
What is the difference between Voltage and EMF? 1. EMF is the voltage generated by a source like battery or generator. 2. We can measure voltage between any two points, but EMF exists only between the two ends of a source. 3. Voltages in a circuit called ‘voltage drops’ are in the opposite direction of EMF and their sum is equal to EMF according to Kirchhoff’s second law. |
this page is very informative & V.V.Good
agree with you
Basically, the Emf supplies the electrical circuit and its components – while the Voltage takes the energy out!
absolutely perfect
awesome really impressed
解释很好。我从这篇文章中获得了很多信息。
假设您有一个封闭的电线环或一盘金属。如果将磁铁通过环或板通过磁场将电源移动，则将在金属丝环或金属板的圆形区域中诱导电流。我们可以通过测量线圈/板的温度来验证并连续振荡它们，以使磁场始终变化，并且电流始终在流动。
Now how does one refer to the Voltage or EMF which induces this current?
If you take the wire loop you cannot say there is a Voltage drop between any two points on the loop because the current is going in a loop. If an electron goes from point A around to point B, (where B is A) once around the loop then to point C (also point A) twice around the loop the same point would be considered to have two completely different Voltages based on the resistance of the wire.
In my opinion, EMF seems to be the correct term here because it is a force which moves the electrons and not a potential drop between points which causes it.