Electrical Current
Current
Current - A net flow of charge in a unit time
Current (A) I = ∆Q Change in Charge (C)
∆t Change in Time (s)
∆t Change in Time (s)
Current in a metal wire is the flow of electrons
A metal is made up of an ionic lattice surrounded by a 'sea' of delocalised electrons
Electrons move about in a wire even without a power source
This travel is chaotic and has no general direction. All electron movements thus cancel all movements out meaning there is no current as there is no net movement
A metal is made up of an ionic lattice surrounded by a 'sea' of delocalised electrons
Electrons move about in a wire even without a power source
This travel is chaotic and has no general direction. All electron movements thus cancel all movements out meaning there is no current as there is no net movement
When connected to a power source electrons move in one direction.
This is called electron drift.
This is called electron drift.
1 Amp = 1 Coulomb of charge per second
Charge Carriers
Charge Carriers carry charge whether its negative (electrons) or positive (ions)
Number of electrons n = Q Total Charge (C)
e- Charge of One electron (C)
e- Charge of One electron (C)
This can be used for photons too
Charge of an electron = 1.6 x 10^-19
Charge of a photon = 3.62 x 10^-19
Charge of an electron = 1.6 x 10^-19
Charge of a photon = 3.62 x 10^-19
Electricians use conventional current where it is viewed the current goes from positive to negative
This is not what happens as the actual electron flow is going from negative to positive as the electrons are repelled by the negative side of the power source
This is not what happens as the actual electron flow is going from negative to positive as the electrons are repelled by the negative side of the power source
Kirchhoff's First Law
At any junction in a circuit, the total current leaving the junction is equal to the total current. It is the Conservation of Charge
Electron Drift Velocity
EDV - The net average velocity of electrons traveling through a metal
I = naVe
Current = Number Density (m^3) x Cross-sectional Area (m^2) x Mean Drift Velocity (m/s) x Electron Charge (C)