The power supply is said to have an electromotive force, or emf. Electromotive force is measured in volts. Electromotive force is not a force. Instead, it is the energy gained by the charge that comes from the chemical energy of the battery. In equation form, B. Internal Resistance
They also possess internal resistances. Incidentally, a pure voltage source is usually referred to as an emf (which stands for electromotive force ). Of course, emf is measured in units of volts. A battery can be modeled as an emf connected in series with a resistor , which represents its internal resistance.
It is the role of the power source to supply the circuit and its components with energy. If the power source is a battery or a cell, chemical energy is converted to electrical energy. However, this process is not always 100 percent efficient. In this section we look into the Electromotive Force (EMF) and internal resistance of batteries and cells.
Electromotive force is not a force. Instead, it is the energy gained by the charge that comes from the chemical energy of the battery. In equation form, B. Internal Resistance All power supplies have some resistance between their terminals, called internal resistance.
A battery delivers maximum power to a circuit when the load resistance is equal to the internal resistance of the battery. When a charge passes through the power supply, it gains electrical energy. The power supply is said to have an electromotive force, or emf. Electromotive force is measured in volts. Electromotive force is not a force.
The power supply has an emf (E) and internal resistance (r). An external resistor (R) (also called a load) is connected in series. A current (I) flows through the circuit. The voltage across the resistor (R) is VR and the voltage across the internal resistance (r) is Vr.