Current - Voltage Flashcards
what is current?
- the rate of flow of charge ( A )
what is 1 amp?
1 amp is equivalent to a charge of 1 Coulomb flowing in one second
1A = 1C/s
what is current in electric circuits?
- the flow of electrons
what is conventional current?
- the flow of positive charge
what is potential difference?
- electrical work done per unit of charge flowing between two points
what is 1 volt?
1 volt is equivalent to the transfer of 1 joule of electrical energy by 1 Coulomb of charge
1V = 1J/C
what happens as electrons flow through a cell?
- they gain energy
- in a Xv cell, every coulomb of charge passing through gains Xj of energy
what happens as electrons flow through a circuit?
- they lose energy
- after leaving a Xv cell, every coulomb of charge will transfer Xj of energy to waste and components
what is resistance?
- a measure of how much the material opposes the flow of electric current
- measured in ohms
what is a resistance of 1 ohm?
- equivalent to a potential difference across a component of 1V which produces a current of 1A through it
what is Ohm’s Law?
Ohms Law states that for a conductor at a constant temperature, the current through it is directly proportional to the potential difference across it
how do can you tell if an electrical component follows ohms law?
- straight line through the origin graphically
explain the I-V graph for a filament lamp
- obeys ohms law for small voltages
- as current increases, temperature of filament increases
- since filament is a metal, higher temperature causes an increase in resistance
- resistance opposes current, causing current to increase at a slower rate
what is a semiconductor diode used for?
- prevents backflow of current
