# Magnetic and Electromagnetic Experiments

Item no.: F18

##### Introduction

In1820, an electromagnetic theory was initiated by Oersted. Here the physical experiment relative to magnetic field induced by a current-carry wire was proposed. During 1820~1827, the theoretic model was further quantified by Ampere’s. In 1831, the so called Faraday’s law amounted the current induced along the closed loop while a time varying magnetic flux, across the sectional area of coils, is undertaken. That also explains the mutual relation between electric current and magnetic field, and has become a fundamental principle for electromagnetic application in our daily life. Base on quantity analysis from theoretic or empirical model, the experimental kits, in this subject, also provides some interesting demo related to electromagnetic demonstration.

##### Objectives

1.Geomagnetic measurement :
Tangent Galvanometer
Determination by the magnetic moment

2.Magnetic effect of electric current and applications :
Current Balance
DC Motor

3.Electromagnetic induction and applications :
Lenz’s law
Self-inductance and mutual inductance
Generator
Transformer
Magnetic communicatio

##### Experiment—Tangent Galvanometer

With rotating angle of magnetic pin measured, axial magnetic field induced from solenoid Baxis could be determined.

##### Experiment—Current Balance

Apparent weight on the load cell, experiment of Lorentz force, could be induced by a current carried by two parallel magnets.

If a magnet is passed through a coil of conducting wire, a voltage is induced (created) in the coil. The faster of the magnet moves through the coil, the greater strength of voltage.

1. 以小磁棒磁力矩推測地磁
2. 以正切電流計測量地磁
3. 電流天平測量實驗
4. 直流馬達模型演示
5. 法拉第定律測量實驗
6. 冷次定律演示
7. 跳環實驗
8. 發電機演示
9. 變壓器測量實驗
10. 電磁通信演示
##### 實驗器材：
1. 鋁製實驗平台 x1
2. 鋁製活動實驗平台含60cm鐵棒及鋁製鐵棒固定滑塊 x1
3. 正切電流計 x1
4. 磁矩實驗器 x1
5. 電流天平 x1
1. 強力平行磁鐵組,磁距可調整以改變中心磁場強度
2. 長直導線組, 以Φ0.5mm漆包線繞製二矩型迴圈各繞20匝, 產生30/40/50/60mm長度四段測試線段
3. 隔磁用泡綿方塊 10x10x10cm
4. 電子天平
5. 導線迴圈用固定夾 x1
6. 直流馬達模型x1
1. 強力磁鐵組, N S磁極各置於鐵棒上分開的塑膠塊,
2. 活動式漆包線迴圈,連接於U型支架上二導電端子
7. 變壓器組 x1
1. 線圈組,匝數N:300 x1 N:900×1
2. 鋁製變壓器固定架
3. EC 型高磁導率軟磁鐵氧體x2
8. 法拉第實驗用透明膠管 x1
9. 冷次定律實驗用磁鐵 x1
10. 冷次定律實驗用鋁管 x1
11. 跳環實驗用鐵芯棒.固定環及鋁環 x1
12. 膠管及鋁管兩用固定夾 x1
13. 發電機模型用可旋轉強力磁場器 x1,及線圈鐵心 x2
14. 收音機x1
15. 拾音喇叭x1
16. 連接導線 x4
17. 聲音輸出線 x1
18. 自備或選購
1. 交直流電源供應器 x1
2. 三用電錶 x1
3. 電腦數據擷取器 x1
4. 電壓感測器 x1
5. 電流感測器 x1