Electricity ⚡

• electricity is a form of energy generated from electrons and can either be static or current
• static electricity is when two objects rub together and a charge is built
• electrons move off one surface, leaving a positive charge and the other surface, leaving it negatively charged
• static electrity is static as they dont move and stay in one area without moving
• the energy usually discharged into the enviromment until both objects are netural, the electrons slowly leave or return to the charged object
• humans can feel this charge and this happens when electrons is rapidlly returning or leaving the charged item, it is normally discharged through heat, light, sound and motion Eg. lightning or a cap when we touch metal
• Eg. a balloon and jumper become charged because they gain/lose electrons, this is static electrity. the charged ballooon then makes the electrons move in the wall, this is an induced charge
• current electrity is the path that an electron takes is a electric circuit.
• the circuit needs to be complete and not have any breaks
• the switch controls whether or not it works
• current electrity is the movement of electrons and is from a batttery or a power source
• electrons flowing throuhg a circuit needs to follow these rules:

  • they move from the negative side to the positive end
  • they must lose all of their energy before going to the start point
  • more electrons take the easier route to the end rather than the difficult one
• label:

  A) positive

  B) negative

  
• each circuit needs:

  a power source, connecting wires and something to use the electrical energy
• wires are made out of metals, like copper because these are good conductors of electricity and heat

  wires are surronded by plastic or rubber, these are good insulators so it does not let the electricity pass through and reach us
• conductors: a material that allos an electric current to pass Eg. silver, gold, seawater
• insulators: a materia that doesnt allow electric current to flow easily Eg. wood, glass, rubber, plastic, oil
• current: the number of electrons flowing past a point in a circuit every second
• symbol of current: I Measured: amps (A)
• conversions:

  A) divided 1000

  B) mA

  C) A

  D) kA

  E) MA

  F) x1000

  
• circuit diagrams: the diagram that shows how the components are arranged in an electric current are called a circuit diagram:

  these are the symbols you use to draw them:

  A) resistor

  B) light globe

  C) V

  
• if the current doesnt have a power source or connecting wire then the electrons dont flow
• if a circuit doesnt have something to use the energy from the electrons then the energy is given to the wires which may overheat and melt, which causes a break or fire, this is called a short circuit and it occurs because of the rule : electrons must lose all their energy befoe they return to the power source"
• voltage (potential difference) descrives the energy gained across a battery/power supply or the energy loss across a component
• batteries or power supply act as electron pumps pushing electrons out of the negative terminal of the battery: giving them energy to carry around the circuit. the electrons lose this energy when they are forced through a resistor/light bulb
• voltage is measured in volts, symbol V
• a voltmeter measures the energy used in a particular section of the circuit
• the voltmeter measures the differcence in the energy of an elecrton on each side of the resistor so ut hugs part of the circuit and is connected
• series circuit is one circuit where all of the components are connected in a single loop/line. electrons can only flow along one path

  
• parallel circuit is one circuit where the components are connected in such a way that the current can flow along a number of paths

  
• with a series circuit:

  every electron passes through each resistor

  a break anywhere will affect the entire circuit

  voltage is split between all resistors
• lights in the circuit will glow dimily as the number of them increase this is because they all share the same voltage
• parallel circuit

  each electron does not pass through each section of the circuit nor the reistor

  a break in the circuit will not affect the whole circuit

  the voltage is not split between each resistor
• in a parallel circuit, globes have a direct link to the battry so each one gets the full voltage from the battery so glow brightly however this uses more enegry so the battery will go more flat quickly
• current

  the current measures the amount of charge flowing around a circuit every second ie. the number of electrons that pass a point in the circuit every second

  it is measued in the unit ampere (a) (amps) by an ammeter

  the current is measured in milliamps (mA) and microamps (uA)

  you must break the circuit to include an ammeter in a circuit if its a series
• the current is the same at every point in the series circuit

  total current is found by adding the circuit at each of the resistors
• the current in a parallel circuit is different at different point in the circuit
• circuits can also be combinations, the current and voltage will depend on the path that the electron takes
• a conventional current can be descrived as the flow of positive charge, we still show the direction of the current to be from the +ve to -ve even though it is electrons that move (they move -ve to +ve)
• resistance (R) measures how difficult it is for the electrons to flow through the wires.