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When the power source delivers current, the measured voltage output is lower than the no-load voltage; the difference is the voltage drop (the product of current and resistance) caused by the internal resistance. The concept of internal resistance applies to all kinds of electrical sources and is useful for analyzing many types of circuits.
During the 1970s, resistance grew stronger through trade unions and strikes, and was then spearheaded by the South African Students' Organisation under Steve Biko's leadership. A medical student, Biko was the main force behind the growth of South Africa's Black Consciousness Movement (BCM), which stressed the need for psychological liberation ...
Internal resistance varies with the age of a battery, but for most commercial batteries the internal resistance is on the order of 1 ohm. When there is a current through a cell, the measured e.m.f. is lower than when there is no current delivered by the cell.
Simplified model for powering a load with resistance R L by a source with voltage V S and resistance R S.. The theorem was originally misunderstood (notably by Joule [4]) to imply that a system consisting of an electric motor driven by a battery could not be more than 50% efficient, since the power dissipated as heat in the battery would always be equal to the power delivered to the motor when ...
One is its internal resistance and the other is its compliance voltage. The compliance voltage is the maximum voltage that the current source can supply to a load. Over a given load range, it is possible for some types of real current sources to exhibit nearly infinite internal resistance.
A real-world voltage source has a very low, but non-zero internal resistance and output impedance, often much less than 1 ohm. Conversely, a current source provides a constant current, as long as the load connected to the source terminals has sufficiently low impedance.
The resistance is measured after replacing all voltage- and current-sources with their internal resistances. That means an ideal voltage source is replaced with a short circuit, and an ideal current source is replaced with an open circuit. Resistance can then be calculated across the terminals using the formulae for series and parallel circuits ...
The government responded to a series of popular uprisings and protests with police brutality, which in turn increased local support for the armed resistance struggle. [142] Internal resistance to the apartheid system in South Africa came from several sectors of society and saw the creation of organisations dedicated variously to peaceful ...