Electricty Flashcards
The electric current is
The rate of flow of charge in the wire or component
The charge is due to
The passage of charged particles–
Referred to as charge carriers
In metals the charge carriers are conduction electrons
The move about inside the metal repeatedly colliding with each other and fixed positive iOns in the metal
When an elector. Current is passed through a salt solution the charge is carried by
Ions
Which are
Charged atoms or molecules
IOns
Charged atoms or molecule
Electrons enter the battery at the
Positive terminal, peace through negative terminal
Ampere Is unit for current
Symbol I
Charge unit is coulomb
Coulomb unit of charge (Q) is equal to
Charge flow in one second when the current is one ampere
For current I, the charge flow /\Q in time /\t is given by
/\ Q= I /\t
Magnitude of charge of one electron is
1.6 x10^ -19
Electrical terms
Conductors
Insulators
Semiconductors
R.E.M.
Insulator- each electron is attached to an
Atom and cannot move away
When a voltage is applied, no current passes through because electrons cannot move through insulator
Metallic conductor- most electrons are attached to atoms but some are d-
Delocalised.
The d- electrons are the charge carriers in the metal
When a voltage is applied these conduction electrons are attached to positive terminal of the metal
Semiconductor- the no. Of charge carriers increases with bigger temp.
And resistance decreases as temp is raised
A pure semi conductor material - intrinsic semiconductor
Conduction is due to electrons that break free from the atoms o the semiconductor