simple circuits

• Current in a series circuit

  the current is the same anywhere in a series circuit
• Current in a parallel cicuit

  the current in each branch adds up to the total current transferred by the cell.
• Circuit Rules: P.D. in Series

  The P.D. of the cell is shared among the components.

  EG. If the P.D. is 6V, and there are 2 identical filament lamps, each lamp will have 3V each,
• What is resistance?

  A measure of how easy it is for current to flow.
• Circuit Rules: P.D. in Parallel

  Each branch after the junction gets the same P.D.
• Circuit Rules: Current in Series


  All components in series have the same current as each other.

  EG. 2 filament lamps will have th same current if they are in SERIES.
• Circuit Rules: Current in Parallel

  Total current into a junction=total current out of a junction.
• What are the conditions needed for charge to flow through a conductor?

  potential difference

  • closed or complete circuit
• for current to flow, it has to be in a closed circuit
• IV Characteristic graph

  A) resistors and wires

  
• IV Characteristic graph

  iv graph

  A) filament lamp

  
• iv characteristic graph

  iv graph

  A) diode

  
• How does resistance change with current?

  as current increases, electrons have more energy. when they flow through a resistor, they collide with the atoms in the resistor. this transfers energy to the atoms, which makes them vibrate more. these increased vibrations make it more difficult for the electrons to flow through. Therefore, as resistance increases, current decreases; they are inversely proportional.
• P.D. in series


  total p.d. is shared between each component
• p.d. in parallel


  p.d. in each component is the same