DOMRAC 3

• Electricity is a form of energy
• Electricity can be produced from chemicals, pressure, lights, heat waves and magnetism
• There are two electrical polarities: positively charged and negatively charged
• Copper has an equal number of protons and electrons
• Electricity


  A form of energy
• Atom


  The smallest particles in matter
• Magnetic fields


  The force between two poles
• Magnetism


  The force between two poles
• Protons

  Positively charged particles
• Electrons


  Negatively charged particles
• Neutrons


  Particles with no charge
• South pole and north pole


  The two magnetic poles
• Polarities

  Positive and negative
• AC/DC


  Types of current
• How electricity is produced by magnetism

  1. Conductor cut through magnetic lines of force between two poles of magnet

  2. Electromotive force is produced

  3. Electric generator has large magnetic field and many turns of wire cutting lines of force
• Atom


  Made up of protons, neutrons, and electrons
• Hydrogen is the simplest atom with 1 proton and 1 electron
• Number of electrons in an atom is the same as the number of protons
• Copper has 29 protons and 29 electrons with 1 electron in the outer orbit, making it a good conductor
• Atoms with few electrons in the outer orbit are good conductors, atoms with several electrons in the outer orbits are poor conductors and are considered insulators
• Direct current


  Travels in one direction only, from negative to positive, has polarity
• Alternating current


  Continually and rapidly reversing, no polarity
• The generator is the main source of electricity, it changes mechanical energy to electrical energy using magnetism
• Ohm's Law


  Relationship between voltage, current, and resistance
• Ohm's Law formulas

  1. Voltage = Current x Resistance

  2. Current = Voltage / Resistance

  3. Resistance = Voltage / Current
• Series circuit


  Two or more loads connected one from another
• Parallel circuit


  Two or more loads connected one beside the other
• Series circuit


  • Voltage is divided across different resistances
  • Total current flows through each resistance
  • Resistances are added together to get total resistance
• Parallel circuit


  • Total voltage is applied across each resistance
  • Current is divided between different loads, total current is sum of all loads
  • Total resistance is less than smallest resistance
• Ohm's Law is the relationship between the three elements of electricity
• Series circuit has one flow of electric current
• E = I x R is the formula for finding resistance
• Parallel circuit has the same value of voltage
• E + E + E is the formula for finding the total amount of resistance in a circuit
• P = I x E is the formula for finding current
• Voltmeter is used to measure voltage
• Ohmmeter is used to measure current
• In a simple circuit all components are connected in parallel
• Amperes is the unit of resistance
• Series circuit


  1. Current is constant

  2. Total voltage is the sum of all voltage