Potentiometer Galvanometer Kirchhoff Law Electromotive force D’Arsonval Galvanometer Kirchhoff Current and Voltage Law

Potentiometer a I b I R I I r  － ＋ 直流電源 D + - 待測電池 F 已知電池 E G A B C R 直流電源 D + - 待測電池 F 已知電池 E G A B C R RpRp 直流電源

D’Arsonval Galvanometer  The angle of deflection of the pointer is directly proportional to the current in the loop  The deflection also depends on the design of the meter τ m =μB, μ=NIA magnetic dipole moment τ s =-κψ, κis the tensional spring constant τ m +τ s =0

Ammeter/Voltmeter the ammeter should have zero resistance so the current being measured is not altered the voltmeter should have infinite resistance so that no current would pass through it

Multimeter x  0 y RoRo R  IcIc RcRc I

Resistance 顏色銀 Silver 金 Gold 黑 Black 棕 B rown 紅 Red 橙 Orange 黃 Yellow 綠 Green 藍 Blue 紫 Violet 灰 Gray 白 White 無色 數值 誤差 ±10%±5%±20%

Kirchhoff’s Rules Junction Rule:  I in =  I out Loop Rule: Loop

Resistors in Series and Parallel

Wheatstone Bridge G A B