4.1 Charge and Current

• Electric current is the rate of flow of charge

  
  

  I = Q/t
• One coulomb is the amount of charge passing a point in 1s when the current is 1A
• The magnitude of charge on an object is expressed as:

  Q= + or - n * e
• Kirchhoff's first law states that the sum of currents entering a junction is equal to the sum of currents leaving the junction

  This is a statement of the conservation of charge
• We refer to charges of ions(+1, -1) as quantised numbers, and are represented as integer multiples of the elementary charge e = 1.60 * 10^-19
• Current is:

  The movement of electrons in conductors

  The movement of ions in Electrolytes
• Direction of conventional current is positive terminal to the negative terminal

  Electron flow is from the negative terminal to the positive terminal