I-V characteristics

• ohmic conductors have...


  constant resistance
• the resistance of ohmic conducts ... change with the current


  doesn't
• the resistance of some resistors and components change, for example...

  - filament lamp

  - diode
• at a constant temperature, the current flowing through a ohmic conductor is...

  directly proportional to the potential difference across it (R is constant in V = IR)
• when an electrical charge flows through a filament lap, it transfers some energy to the ... store of the filament, which is designed to heat up

  thermal energy
• in a filament lamp, resistance increases with...

  temperature, so as the current increases, the filament lamp heats up more and the resistance increases
• for diodes the resistance depends on...

  direction of current - it has incredibly high resistance in the opposite direction, so current will not flow
• the term I-V characteristic refers to...

  a graph which shows how the current flowing through a component changes as the potential difference across it is increased
• linear components have...


  an I-V characteristic that's a straight line (e.g. an ohmic conductor)
• non-linear components have...


  a curved I-V characteristic (e.g. a filament lamp or a diode)
• ohmic conductor I-V characteristic

  
• what is an ohmic conductor?

  a resistor in which the current is directly proportional to the potential difference at a constant temperature
• filament lamp I-V characteristic

  
• what is a filament lamp?


  a common type of light bulb which heats up as it produces light
• diode I-V characteristic

  
• what is a diode?

  a component that only allows current to flow in one direction