Basic Electronics Notes

Learning Competencies

  • Enumerate different types of electricity.
  • Explain methods of producing electricity and its sources.
  • Identify sources of electricity.
  • Recognize common electrical conductors, insulators, and their uses.

Electricity

  • Electricity is the flow of electrical power or charge, produced by forcing electrons in and out of atoms.
  • It is a secondary energy source, converted from primary sources like coal, natural gas, oil, nuclear power, and other natural sources.
  • Energy sources for electricity can be renewable or non-renewable, but electricity itself is neither.

Types of Electricity

  • Two types: Static Electricity and Current Electricity.

Static Electricity

  • Made by rubbing objects together, creating friction.
  • Electrical charges build up on a material's surface.
  • Objects may be attracted to each other or create a spark.
  • Example: Rubbing a balloon on wool.
    • Before rubbing, the balloon and wool are neutral, with equal numbers of protons and electrons.
    • Rubbing transfers electrons from the wool to the rubber due to differences in electron attraction.
    • The balloon becomes negatively charged (gains electrons), and the wool becomes positively charged (loses electrons).

Current Electricity

  • Flow of electric charge across an electrical field.
  • Current is the rate of flow of electrons, measured in amperes.
  • Requires a conductor, usually copper wire.
  • Analogous to a river's current: the speed of the river is like the speed of the current.
  • Current measures the amount of energy transferred over time, which is a flow of electrons.
  • One result of current is the heating of the conductor.
  • Sources include chemical reactions in a battery and generators.
  • A generator produces electricity by turning a coil of copper inside a magnetic field. Power plants use electromagnets spinning inside copper coils.
Direct Current (DC)
  • Energy flows in the same direction such as from a battery.
Alternating Current (AC)
  • Energy turns on and off in positive and negative directions such as plugs in the wall.

Methods of Producing Electricity

Chemical

  • Example: Battery
  • Stores chemical energy and converts it to electrical energy.
  • Chemical reactions involve electron flow from one electrode to another through an external circuit.
  • Charged ions also flow through an electrolyte solution.
  • Different electrodes and electrolytes affect the battery's function, energy storage, and voltage.

Friction

  • Static electricity is produced through friction.
  • Materials rubbing together cause electron transfer.
  • The materials used determine the type of charge.

Magnetism

  • Uses a conductor and a moving magnetic field to produce electricity.
  • Magnetic field movement dislodges valence electrons from the copper atoms.
  • Used by generators.

Pressure

  • Applying pressure to certain materials, like crystals, dislodges electrons.
  • Pressure causes electrons to leave one side and accumulate on the other.
  • Releasing pressure returns electrons to their orbits.

Heat

  • Some materials readily give up electrons, while others accept them.
  • Example: Joining copper and zinc causes electrons to transfer from copper to zinc.
  • The strength of the charge depends on the temperature and when temperature rises, increases the energy which releases more electrons and creates a higher voltage.
  • Application: Thermocouple.

Light

  • Photons strike the surface of some materials (potassium, sodium, lithium), releasing electrons.
  • Releasing electrons causes the material to gain a positive charge.
  • Released electrons travel to an adjacent material, which becomes negatively charged.
  • Terminals connected to these materials provide voltage.
  • Electrical power production using light is called the photovoltaic process, commonly seen in solar panels.

Electricity Generation Sources

Hydropower

  • Uses flowing water to create electricity.
  • Clean and renewable resource.

Nuclear Power

  • Nuclear fission generates heat.
  • Heat generates steam that rotates turbines to generate electricity.

Coal

  • Abundant and inexpensive energy source.
  • Provides 40% of the world’s electricity.

Wind

  • Renewable energy source with relatively little impact, apart from aesthetic and noise concerns.
  • Energy storage technology impacts the ability to incorporate intermittent electricity supplies like wind power.

Solar

  • Solar photovoltaic converts sunlight to direct current electricity using semiconductors.
  • Solar thermal uses the sun’s heat.

Crude Oil

  • Mostly used for transportation or home heating, with a small percentage used as a fuel for electricity generating plants.

Electric Circuits

  • Path for transmitting electric current.
  • Includes a device that gives energy to charged particles (battery or generator).
  • Devices that use current (lamps, electric motors, computers).
  • Connecting wires or transmission lines.
  • Basic laws describing electric circuits: Ohm’s law and Kirchhoff’s rules.

Types of Electric Circuits

Direct-Current Circuit
  • Carries current that flows in one direction.
Alternating-Current Circuit
  • Carries current that pulsates back and forth many times each second.
Series Circuit
  • Current flows through each component.
Parallel Circuit
  • Current divides and flows through branches.
  • Voltage across each branch is the same, but currents may vary.
  • Batteries connected in parallel provide greater current but the same voltage.

Electrical Conductors and Insulators

  • A conductor allows the flow of charge (electrical current) in one or more directions.
  • Metals are common electrical conductors.
  • Electrical current is generated by the flow of negatively charged electrons, positively charged holes, and positive or negative ions in some cases.
  • An electrical insulator is a material in which electric current does not flow freely.
  • The atoms of the insulator have tightly bound electrons which cannot readily move.
  • Insulators have higher resistivity than semiconductors or conductors.
  • Non-metals are common examples.

Resistivity and Conductivity Table at 20∘C20^\circ C

Materialρ\rho (Ω⋅m\Omega \cdot m) at 20∘C20 ^\circ Cσ\sigma (S/m) at 20∘C20 ^\circ C
Silver1.59×10−81.59 \times 10^{-8}6.30×1076.30 \times 10^{7}
Copper1.68×10−81.68 \times 10^{-8}5.96×1075.96 \times 10^{7}
Annealed copper1.72×10−81.72 \times 10^{-8}5.80×1075.80 \times 10^{7}
Gold2.44×10−82.44 \times 10^{-8}4.10×1074.10 \times 10^{7}
Aluminum2.82×10−82.82 \times 10^{-8}3.5×1073.5 \times 10^{7}
Calcium3.36×10−83.36 \times 10^{-8}2.98×1072.98 \times 10^{7}
Tungsten5.60×10−85.60 \times 10^{-8}1.79×1071.79 \times 10^{7}
Zinc5.90×10−85.90 \times 10^{-8}1.69×1071.69 \times 10^{7}
Nickel6.99×10−86.99 \times 10^{-8}1.43×1071.43 \times 10^{7}
Lithium9.28×10−89.28 \times 10^{-8}1.08×1071.08 \times 10^{7}
Iron1.0×10−71.0 \times 10^{-7}1.00×1071.00 \times 10^{7}
Platinum1.06×10−71.06 \times 10^{-7}9.43×1069.43 \times 10^{6}
Tin1.09×10−71.09 \times 10^{-7}9.17×1069.17 \times 10^{6}
Carbon steel (1010)1.43×10−71.43 \times 10^{-7}
Lead2.2×10−72.2 \times 10^{-7}4.55×1064.55 \times 10^{6}
Titanium4.20×10−74.20 \times 10^{-7}2.38×1062.38 \times 10^{6}
Grain oriented electrical steel4.60×10−74.60 \times 10^{-7}2.17×1062.17 \times 10^{6}
Manganin4.82×10−74.82 \times 10^{-7}2.07×1062.07 \times 10^{6}
Constantan4.9×10−74.9 \times 10^{-7}2.04×1062.04 \times 10^{6}
Stainless steel6.9×10−76.9 \times 10^{-7}1.45×1061.45 \times 10^{6}
Mercury9.8×10−79.8 \times 10^{-7}1.02×1061.02 \times 10^{6}
Nichrome1.10×10−61.10 \times 10^{-6}9.09×1059.09 \times 10^{5}
GaAs5×10−75 \times 10^{-7} to 10×10−310 \times 10^{-3}5×10−85 \times 10^{-8} to 10310^{3}
  • Silver conducts electricity best.