earthing 後的CIRCUIT還有電子流?

咁點解在這點之後去到battery既wire 仲有current

Current would flow when there is a potential difference. Earthing a point in the circuit only defines that point is at earth potential (i.e. zero volt). There will not be any current leaking to earth from that point because both (the point and earth) are at the same zero potential. There is no potential difference to drive current to flow to earth.

The battery maintains a potential difference in the circuit. As long as the circuit is complete, the potential difference given by the battery casues current to flow.

同埋果段wire既potential係negative(如果有resistors), 好似好怪, negative 又有冇意思?

Potentials can be +ve or -ve, or even zero. As said above, current flows because of potential difference. A point "after" the earthing point (in the direction of current flow) is obviously below earth potential (zero volt), hence would have negative potential value. It is because of the difference of potential between the earthing point (zero volt) and the point in question (a -ve potential) that drives the flow of current.

咁earth左又有咩用?
Generally, earthing provides steady potentials at all points in the circuit.

(咁earth左又有咩用?)
It should be a potective circuit to protect the circuit from high voltage pulse shock!

(EARTH左) only means no electron flowing, does not mean electrons 去晒個地球!

(咁點解在這點之後去到battery既wire 仲有current)
should be the leakage of the circuit.

果段wire既potential係negative(如果有resistors),
negative potential is the relative potential only, it depends on which two points you are comparing. When you measure a point with +, if you reverse the measure tool, you can get - .


2009-11-04 16:38:57 補充：
(EARTH左, electrons 去晒個地球) will not apply to electronic circuit!
It only apply to a charge rod ,with different no. of electrons and protons, which will be neutralise by earth!

係一個CIRCUIT入面一點俾人EARTH左 not equal to electrons 去晒個地球


If its a DC Circuits,you no need to earthing,.

But if its a regular AC Circuit,Earth does not have current,so you say electrons 去晒個地球 is not current,when current flows to earth,its Earth Short Circuit(對地短路)or Earth Leakage((對地漏電),those are abnormal,

Earthing Does Not Affact The Voltage,It About Which Way The Current Flows.

Why The Voltage is Negative?resistors Always Afact The Current,Its Not About The Voltage.