electricity
number density
number of free charge carries per unit volume
current
rate of flow of charge
voltage
energy transferred per unit charge, from electrical energy to other forms
emf
energy per unit charge from other forms to electrical - work done to charge carriers
internal resistance
resistance within components which dissipates energy and causes loss of voltage
kirchoffs 1st law
the sum of the currents entering a function is equal to sum of the currents out, conservation of charge
kirchoffs 2nd law
sum of the emf in a closed circuit is equal to the sum of potential difference, conservation of energy
conventional current
electrons move from positive to negative
drift velocity
average velocity of the charge carriers travelling through a conuctor I = Anev
power
rate of work done and energy transferred to an appliance per second
ohms law
current is proportional to potential difference for a conductor at a constant temperature
resistance
the difficulty for a current to flow through a conductor
resistivity
measures the extent to which a material opposes the flow of electric current through it
diode
A component that allows current through in one direction only heavy resistance in other directions