良好的安培計應有高電阻還是底電阻?試扼要解釋

A good ammeter should have negligible resistance. The reason is that an ammeter meaures current in a circuit. As such, current from the circuit needs to pass through the ammeter (this is the reason why the ammeter has to be connected in series). A ammeter of negligible resistance would then give little disruption to the original current, otherwise the measurement is not accurate.

On the other hand, a voltmeter measures the potential difference between two points (this the the reason why it needs to be connected in parallel). Hence, it should have very high resistance in order not to draw any current from the circuit. Otherwise the original potential difference is altered and the measurement will not be accurate.

唔係唔係..果3分3分係題目俾既分黎,我諗住提供埋可以有線索答point

kai fu
你好似計錯數，3分+3分應該係6分，爲何只得5分。

2011-01-19 00:43:50 補充：
良好的安培計應有高電阻還是底電阻?試扼要解釋。(3分)

答案係 : 低電阻唔係底電阻(串聯負載)


良好的伏特計應有高電阻還是底電阻?試扼要解釋。(3分)

答案係 : 高電阻(並聯電源)

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