series + parallel circuits

• series circuit - a circuit has only one path for current to travel

  • eg. Christmas lights
• parallel circuit - a circuit that has more than one path for current to travel

  • eg. house lights
• series circuits

  • electrons must travel through all components of the circuit
  • if one part of a circuit is not connected, all electrons are blocked and the current stops
• voltage + current in series circuits

  • each load uses a portion of the total voltage supplied by the battery
  • total voltage = sum of voltages used up on loads
  • current in each part of a series is equal
• resistors in series

  • increase total resistance of circuit
  • increased total resistance = decreased total current
• in electric circuits, the charge that leaves a battery uses up all its voltage before it returns to the battery
• parallel circuits

  • closed pathway that has several different paths for electrons to travel in order to return to the battery
• voltage + current of parallel circuits

  • since all pathways connect at the same location, the voltage used up on each pathway is identical
  • loads in parallel have the same voltage
• junction point - where a circuit divides into multiple pathways

  • no current is created/destroyed, only split into different pathways
  • current entering must divide among possible paths
  • amount of current through each pathway depends on the resistance of the path
  • total current entering the junction point must equal the sum of current leaving the junction point
• resistors in parallel

  • when a resistor is placed in parallel with another resistor, you create another pathway so the total resistance must decrease
  • more current will travel through paths with lower resistance