topic 2 electricity

• dangers of electrostatic charging in aircrafts is that a build up of static charge can result in sparks which can set the fuel alight
• a charge is carried by an electron, opposite charges attract, like charges repel. gain of electrons is negative charge, loss of electrons is positive charge
• conductor is a substance that lets electricity flow through it for example, iron, gold and copper
• live wire, carries current to the appliance at a high voltage, around 230v its brown and on the right
• a series circuit has all its components wired in the same loop
• total current in a parallel circuit is equal to the sum of the current on each branch
• voltage in a parallel circuit is the same in each branch
• current in a series circuit, current is the same in the entire circuit
• the resistance of a conductor is the measure of how easy or hard it is for current to flow through it, the longer the wire the more resistant it can become. however resistance changes if the wire heats up
• voltage in a series circuit is shared amongst devices, the Total voltage in the circuit is the sum of all voltages in each device
• resistance in a series circuit is shared amongst devices the total resistance in the circuit is the sum of all resistances in each device
• direct current is electric current that always flows in one direction. it is produced by cells and batteries
• the total current entering a circuits junction is exactly equal to the Total current leaving the same junction, no charge is lost
• electrical power is the rate at which energy is transferred in a circuit. all electrical appliances have a power rating
• resistance in a parallel circuit, the resistance on each branch is larger then the total resistance
• neutral wire completes the circuit and carries current away from the appliance, it is nearly 0v. its blue and on the left
• a parallel circuit has devices on different loops such as the current is split at branches
• mains electricity, electricity is generated in power stations and then carried around the uk by national grid, mains electricity is generated by the national grid and comes to homes
• earth wire is a safety wire and connects the metal case of the appliance to the earth. this stops a fault making the appliance live, it is striped and in the middle
• energy transferred equation, energy transferred = charge x voltage
• non ohmic conductor is any electrical device that does not follow ohms law. they have specific functions other than regulating voltage and current
• ohmic conductor is devices which follow ohms law 100 percent of the time e.g a fixed resistor
• resistance is a measure of the opposition to current flow in an electrical circuit
• when resistance is increased in a circuit for example by adding more electrical components, the current decreases
• current Is the rate of flow of charge of electrons around a circuit
• voltage is the energy transferred per unit charge passed, the volt is joule per coulomb
• lamps stay bright if you add more in parallel, components continue to work even if one has failed
• ohms law links resistance, current and voltage. in ohms law current is always directly proportional to voltage where's resistance is constant
• energy transferred equation, energy transferred = current x voltage x time
• power equation, power = current x voltage
• voltage equation, voltage = current x resistance
• charge equation, charge = current x time
• insulator is a substance that does not let electricity flow through it, plastic, wood and glass
• spray painting, as the drops all carry the same charge they repel and spread out forming a Thin spray, the object it attracts has an opposite charge so they attract
• inkjet printer, each spot of ink is given a charge so that as it falls between a pair of deflecting plates, electrostatic forces direct it to the correct position
• photocopier is when positive charges are sprayed onto a turning drum whose surface is covered in a metal called selenium. white parts of the paper reflect light onto the drum the dark printed parts do not. a negatively charged carbon powder called toner is blown across the drum and sticks to just those parts of the drum that are charged
• charging by friction, if you rub a balloon together with a woollen jumper it will steal some of the electrons and leave the jumper positive.
• Lamp is an electrical component which converts electrical energy to heat up a filament and converts it into light energy

  
• LED is a light emitting diode, this allows current to flow in one way. This helps check if the circuits are connected correctly

  
• Double insulation is a method of protection against electric shock consisting of An extra layer of insulating over the basic insulation