Lesson2ApplicationofOhm’sLawKeywords■circuit

[‘s?k?t]

電路、線路■

arrows['?ro]箭頭■series['siriz]串聯■generator['d??n?,ret?]發電機、發生器■parallel[‘p?r?,l?l]并聯■

conductors[k?n'd?kt?]導體■series-parallel['siriz]['p?r?,l?l]

串并聯的

■apparatus[,?p?'ret?s]儀器■path[p?θ]通道■voltagedrop['volt?d?][drɑp]電壓降■current[‘k??nt]電流■potentialdifference[p?'t?n??l]['d?f?r?ns]電位差■divides

[d?'va?d]分流、分開■circuitelement['s?k?t]['?l?m?nt]電路元件■

points[p??nt]

點，節點

■

terminal['t?m?n!]

終點、末端■resistances

[r?'z?st?ns]

電阻

■termed

稱為（=call）■

arrangements[?'rend?m?nt]裝置、設備

■no-load

空載（無負載）■

splits[spl?t]分流、分開

■

apparent[?'p?r?nt]顯然的、明顯的■branches分支，支路（電路）

■internal[?n't?n!]內部的■工作任務：如何調節燈的亮度？■學習目標：掌握最簡單的電路的基本原理，理解歐姆定律中元件串聯，并聯的含義，掌握電路中各個電學參量之間的關系■

重點難點：串聯、并聯電路的電學參量之間的關系■

推薦學時：6學時Howtomonitorthebrightnessofalightinacircuit?

Whichsegmentdecidesthebrightnessofthelightinthecircuit?Wecanseethebrightnessadjustablelightanywhereinthemarketorinourhome.Rotatetheknob,thelightwillturnbrilliantorturndark.So,whenyourotatetheknob,whathaschangedinthecircuit?

■Aseriescircuitisoneinwhichthecurrentflowsinasinglecontinouspathandisofthesamevalueateverypointincircuit

(figure1).

ResistancebatteryR1ER2Figure1-aFigure1-b

■Inaparallelcircuittherearetwoormorecurrentpathsbwtweentwopointsinthecircuit,asshowninfigure2.R1

R2

AB

－

＋

Figure2■Figure3.showsaseries-parallelcircuit.

ABR1R2R2－

＋

－

＋

R1R2R3R4ABFigure3-aFigure3-b

■Avolagesourcehavingalowinternalresistanceismoredesirable.R1R2R3R4ABC－

＋

Figure