# 電壓

 喺好多電器入面，電芯都係電壓嘅來源。

## 電磁學研究

### 定義

${\displaystyle W=\mathbf {F} \cdot \Delta \mathbf {r} \,}$ 嘅定義；詳情睇牛頓力學）；${\displaystyle [1]}$

${\displaystyle W_{0}={{\boldsymbol {F_{0}}}\cdot \Delta \mathbf {dr} }+{{\boldsymbol {F_{1}}}\cdot \Delta \mathbf {dr} }+{{\boldsymbol {F_{2}}}\cdot \Delta \mathbf {dr} }+...\,}$ ${\displaystyle [2]}$

${\displaystyle [2]}$  呢條式當中，${\displaystyle {\boldsymbol {F_{i}}}}$  係「粒帶電粒子喺 ${\displaystyle i}$  嗰點受嘅靜電力」（而 ${\displaystyle i}$ ${\displaystyle x_{A}}$ ${\displaystyle x_{B}}$  之間是但一點），而 ${\displaystyle \Delta \mathbf {dr} }$  係一個差唔多係等如無窮小量，代表咗兩點之間嘅距離嘅一極細橛。基於 ${\displaystyle [2]}$ ，噉「一個單位嘅電荷受到股電場嘅力影響而由 ${\displaystyle x_{A}}$  移去 ${\displaystyle x_{B}}$  嗰度佢所釋放嘅電勢能」就係

${\displaystyle V_{\mathbf {E} }={{{\boldsymbol {F_{0}}} \over q_{0}}\cdot \Delta \mathbf {dr} }+{{{\boldsymbol {F_{1}}} \over q_{0}}\cdot \Delta \mathbf {dr} }+{{{\boldsymbol {F_{2}}} \over q_{0}}\cdot \Delta \mathbf {dr} }+...\,}$ ${\displaystyle [3]}$ ）－就係「電壓」嘅定義；

${\displaystyle [3]}$  呢條式用積分（詳情睇微積分）形式寫出嚟嘅話係

${\displaystyle V_{\mathbf {E} }=\int _{x_{B}}^{x_{A}}{{\boldsymbol {F}} \over q_{0}}\cdot \Delta \mathbf {dr} \,}$ ${\displaystyle [4]}$ ）；仲有得寫做
${\displaystyle V_{\mathbf {E} }=\int _{x_{B}}^{x_{A}}\mathbf {E} \cdot \Delta \mathbf {dr} \,}$ ${\displaystyle [5]}$ ）；${\displaystyle \mathbf {E} }$  係電場嘅強度。

## 攷

1. IEV (International Electrotechnical Vocabulary) ref 121-11-27
2. Demetrius T. Paris and F. Kenneth Hurd, Basic Electromagnetic Theory, McGraw-Hill, New York 1969.
3. P. Hammond, Electromagnetism for Engineers, p. 135, Pergamon Press 1969.
4. "ELECTRICITY AND ELECTRICAL HAZARDS". 原著喺2018年3月20號歸檔. 喺2018年3月17號搵到.
5. National Institute for Occupational Safety and Health - Fatality Assessment and Control Evaluation: Cases of high-voltage related casualties. Retrieved on November 24, 2008.
6. Griffiths, David J. (2013). Introduction to Electrodynamics (4th ed.). Boston, Mas.: Pearson.
7. ALL ABOUT CIRCUITS - Ground and Other Reference Points
8. NATIONAL INSTRUMENTS - How To Measure Voltage