# Theorem of テブナン

It is a method that the theorem (テブナン のていり, Thevenin's theorem) of テブナン converts an electric current drifting to the voltage and the load to be provided when I connected load to the electric circuit including a large number of DC power supply into a voltage source with the single internal resistance and demands it.

I am announced in 1883 by French postal administration, engineer of the ministry of telegraphic communication, ) (Léon Charles Thévenin) and was called "a theorem of テブナン", but am called the theorem (Helmholtz-Thevenin's theorem) of Helmholtz - テブナン because what was announced in 1853 before it than it by German physicist, Hellman phone Helmholtz had it pointed out by German physicist ) (Hans Ferdinand Mayer) in 1950. In addition, from the situation in deference to Helmholtz being the first publisher, I distinguish it from a theorem of Helmholtz in the mathematics (vector analysis) and may be called "Helmholtz equivalent circuit".

After the name of Hidetaro Ho who announced equivalent voltage source indication (とうかでんあつげんひょうじ), that it is established in the case of an AC power supply again in Japan in 1922, I say with the theorem (one, テブナン のていり) of Otori - テブナン. By the religious awakening of Kanesaburo Kurokawa who was a professor at Waseda University as for this [1].

## Summary

I can change a voltage source, a current source, any flight recorder only including resistance to the テブナン equivalent circuit

The next relations are established when I do the voltage between terminal A-B when I connected IL, load by an electric current drifting to the RL, load with a resistance level of the load to connect the internal resistance of the circuitry that saw the opening voltage between output terminal A-B of the circuitry in a right figure from the Vth, terminal A-B interval to between Rth, A-B with VL.

${\displaystyle I_{L}={\frac {1}{R_{th}+R_{L}}}V_{th}}$
${\displaystyle V_{L}={\frac {R_{L}}{R_{th}+R_{L}}}V_{th}}$

In addition, the voltage source throws a short circuit, the current source open and should think when you demand the internal resistance of the circuitry. But naturally you must consider it when there is internal resistance to the voltage, a current source.

## Footnote

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1. In ^ Masamitsu Kawakami "basic electric circuit I linear routine (1)" 1, CORONA PUBLISHING CO.,LTD. 〈 electron communication congress University lecture 13>, 1967, I make version up. ISBN 4339000795 OCLC 47515988.