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
The voltage across the terminals of a battery, for example, is less than the emf when the battery supplies current, and it declines further as the battery is depleted or loaded down. However, if the device’s output voltage can be measured without drawing current, then output voltage will equal emf (even for a very depleted battery).
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.
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. Instead, it is the energy gained by the charge that comes from the chemical energy of the battery. In equation form,
This implies that the battery’s output voltage is reduced by the overload. The reason for the decrease in output voltage for depleted or overloaded batteries is that all voltage sources have two fundamental parts—a source of electrical energy and an internal resistance. Let us examine both. You can think of many different types of voltage sources.
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.