Name: load matching in thevenin circuits
Uploaded: 2024-04-11T12:48:31.000Z
Duration: 1 min 16 s
Channel: JoVE

実際のアプリケーションでは、回路はソースから負荷に最大の電力を供給するように設計されています。
テブナン等価回路は、線形回路が供給できる最大電力を決定できます。
供給される電力は、負荷抵抗と電流の2乗の積です。負荷抵抗が変化すると変化します。
電力を最大化する負荷抵抗値を特定するために、微分計算が使用されます。この式を単純化すると、最適な負荷抵抗値が得られます。
この抵抗値を電力の2次導関数に代入すると負の値となり、最大電力の条件が確定します。
得られた抵抗値により、最大電力を計算できます。負荷抵抗がテブナン抵抗と一致しない場合、供給される実際の電力はこの最大値から逸脱します。
最大電力伝達定理によれば、負荷抵抗がテブナン抵抗と一致するときに最大の電力伝送が発生します。
既知のパラメータのバッテリを、既知の値の2つの抵抗器で接続したとします。バッテリーの内部抵抗と一致する抵抗が最大の電力を受け取ります。

最大の電力伝達

電気通信などの工学分野における多くの実際的な応用では、接続された負荷への電力供給を最適化する必要があります。ただし、この追求には固有の内部損失が伴い、負荷に供給される電力と同等またはそれを超える可能性があります。テブナン等価回路は、線形回路が負荷に供給できる最大電力を見つけるのに役立ちます。この文脈では、負荷抵抗は調整できることが想定されています。

Figure 1 に示すように、負荷を維持しながら回路全体をテブナンの等価回路に置き換えることにより、次のようになります。

<img alt="Figure1" src="/files/ftp_upload/15055/15055_PT_Figure_1.svg" style="text-align: center; height: 140px;">
Figure 1: 最大電力伝送に使用される回路

負荷に供給される電力は次の式で与えられます。
<img alt="Equation1" src="/files/ftp_upload/15055/15055_PT_Equation_1.svg" style="text-align: center; height: 40px;">.................(1)

特定の回路では、テブナンの等価抵抗と電圧は固定されています。負荷抵抗の変化によって電力供給の変動は、負荷抵抗が非常に小さいか非常に大きい場合には最小になりますが、負荷抵抗がゼロから無限大までの値の場合は最大になります。最大電力伝送は、負荷抵抗がテブナン抵抗に等しい時に達成されます。

<img alt="Equation2" src="/files/ftp_upload/15055/15055_PT_Equation_2.svg" style="text-align: center; height: 14px;">.................(2)

これは最大電力伝達定理として知られています。式 1 と 2 を使用すると、伝達される最大電力の式が得られ、次のように表されます。

<img alt="Equation3" src="/files/ftp_upload/15055/15055_PT_Equation_3.svg" style="text-align: center; height: 40px;">..................(3)

この式は、式 2 が有効な場合にのみ適用されます。それ以外の場合、負荷に供給される電力は式 2 を使用して決定されます。 1.

実際のアプリケーションでは、回路はソースから負荷に最大の電力を供給するように設計されています。
テブナン等価回路は、最大値を決定できます...

Education

JoVE Core

Electrical Engineering

電気工学

Unit 1

ユニット1

DC Circuit Analysis

直流回路解析

KEY TERMS AND CONCEPTS

主要用語および概念

Maximum Power Transfer

load matching in thevenin circuits

Load matching in Thevenin circuits helps a source deliver the most power to a connected load. This matters in engineering fields such as telecommunications, where power delivery must be optimized. Even then, internal losses can be significant and may equal or exceed the power sent to the load.

The Thevenin equivalent circuit is a useful way to study this situation. It replaces the full linear circuit with a simpler source and resistance while keeping the load in place. In this setup, the load resistance is assumed to be adjustable, so the power delivered to it can be tested across different values.

For a fixed circuit, the Thevenin equivalent voltage and resistance do not change. The load power changes only a little when the load resistance is very small or very large. It reaches a maximum at one value between zero and infinity.

The maximum power occurs when the load resistance equals the Thevenin resistance. This condition is called the maximum power transfer theorem. Using the load-power equation and this matching rule, the maximum transferred power can be found. If the matching condition is not met, the load power is determined from the general power equation instead.

Load Matching in Thevenin Circuits

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maximum power transfer

Load matching in Thevenin circuits helps a source deliver the most power to a connected load. This matters in engineering fields such as telecommunications, where power delivery must be optimized. Even then, internal losses can be significant and may equal or exceed the power sent to the load. The Thevenin equivalent circuit is a useful way to study this situation. It replaces the full linear circuit with a simpler source and resistance while keeping the load in place. In this setup, the load...

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key terms and concepts

Learn how Thevenin equivalent circuits predict maximum power transfer when load resistance matches Thevenin resistance in linear circuits.

Load Matching in Thevenin Circuits | JoVE K12

JoVE Core 電気工学 は、電気回路の基本概念と回路解析テクニックを網羅したアニメーションビデオシリーズです。オペアンプと回路変換および 1 次・ 2 次回路の概念を網羅しています。実験を撮影した実写動画では、設計例や現代社会での応用が含まれており、複雑な概念も分かりやすく学習いただけます。

electrical engineering

Load Matching in Thevenin Circuits

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