electricity

• current in a circuit = flow of electrical charges
• potential difference = provides 'push'
• resistance = restricts the current
• electrical wires are made from metal. so they have a regular lattice structure . outer electrons are free to move which forms a current . collisions of electrons will reduce current
• conductors have low resistance
• insulators have high resistance
• in a series circuit resistance across all components increase as more components are added
• resistors in parallel ; resistors decrease as more components are added as more paths to flow
• in LDRs resistance is decreased as light intensity increases
• in thermistors , as resistance decreases the temperature increases
• current is measured in A amps
• potential difference is measured in V volts
• resistance is measured in OHMS
• how do you know if a circuit is series or parallel

  a series circuit has no branches
• what is AC alternating current

  changes direction
• what is DC direct current

  flows one direction
• what colour is the live wire

  brown
• what colour is the neutral wire

  blue
• what colour is the earth wire


  green
• what does the step-up transformer do

  increase voltage

  reduce current
• what does the step - down transformer do

  reduce voltage