Basic Electrical Concepts Flashcards
(35 cards)
Define static electricity and how is it formed?
The charge set up set up by stationary particles of ions and electrons, produced by friction, heat or pressure.
Ref: Pg. 559 Electrical Principles
Where is static electricity used in the electro technology industry?
Dust Filtration
Exhaust stacks of power stations to stop pollution
Painting and chrome baths
Making sandpaper
Why would you take precautions against static electricity build up when working with electronics?
To not damage delicate electrical components with the static charge.
Typically, how are fossil fuels used to produce electricity?
Burnt to create heat.
What is the definition of renewable energy?
Energy from a source that is not depleted when used, such as wind or solar power.
Name four sources of renewable energy.
- Wind
- Solar
- Tidal and Wave
- Geothermal
- Hydropower
- Biomass
Why is electricity transmitted at such high voltages?
Electricity is transmitted at high voltages to reduce energy loss as heat in the transmission lines, making long-distance power delivery more efficient.
It also ensures that the volt drop is negligible in a percentage form.
Name two voltages levels used to to transmit electricity in W.A?
- 22kV
- 33kV
- 66kV
- 132kV
- 220kV
- 330kV
What is the name of the device that steps up and steps down the voltage levels for transmition?
A transformer.
What voltage levels are available for an electrical consumer in W.A?
240V and 415V
What is the voltage level between two of the phases in a four wire system in WA? (3 phase)
415V
What is the voltage level between Neutral and Earth in a four wire system in WA?
0V unless in a fault condition.
Describe a simple diagram showing the relationship between the major parts of an atom, including the plarity of each.
A simple diagram of an atom shows:
• A nucleus at the center, containing:
• Protons (positive charge)
• Neutrons (no charge)
• Electrons (negative charge) orbiting the nucleus in shells or energy levels.
Polarity:
• Protons = positive
• Neutrons = neutral
• Electrons = negative
The atom is overall neutral if it has the same number of protons and electrons.
What is the main difference between an electrical conductor and an insulator with regard to their atomic structure?
The main difference lies in how tightly electrons are held:
• Conductors have free electrons that can move easily between atoms, allowing electricity to flow.
• Insulators have tightly bound electrons that cannot move freely, preventing electrical flow.
Is a vacuum an insulator, a conductor or a semi conductor?
A vacuum is an insulator — it contains no particles, so it does not conduct electricity under normal conditions.
However, in special conditions (like in vacuum tubes or high voltages), electrons can travel through a vacuum, but this requires external energy and equipment. So by nature, a vacuum is an excellent insulator.
What is the special property of a semi-conductor? Name two semi-conductors.
A semiconductor has a special property: it can conduct electricity under certain conditions, but act as an insulator under others. This makes it ideal for controlling electrical signals.
Two common semiconductors:
1. Silicon (Si)
2. Germanium (Ge)
These materials are used in transistors, diodes, and integrated circuits.
Some other, but less common, semi conductors are:
Elemental Semiconductors:
• Carbon (in the form of graphene or diamond under special conditions)
• Tin (α-tin or grey tin) – less commonly used
Compound Semiconductors:
• Gallium Arsenide (GaAs) – used in high-speed electronics and solar cells
• Gallium Nitride (GaN) – used in LEDs and power electronics
• Indium Phosphide (InP) – used in lasers and high-frequency applications
• Cadmium Telluride (CdTe) – used in solar panels
• Zinc Oxide (ZnO) – used in transparent electronics and sensors
• Silicon Carbide (SiC) – used in high-power and high-temperature applications
Name two common conductive materials used in the electro technology trades.
Common conductive materials used in the electrotechnology trades include:
1. Copper – most widely used for wires and cables due to excellent conductivity and flexibility
2. Aluminium – used in overhead power lines and some wiring; lighter and cheaper than copper
3. Gold – used in high-end electronics and connectors due to corrosion resistance
4. Silver – best conductor of all metals, used in specialized components
5. Brass – used in electrical connectors and terminals
6. Steel (galvanized or stainless) – used where strength is needed, but conductivity is lower
7. Carbon (graphite) – used in brushes for motors and certain resistive applications
Name two common insulative materials used in the electrotechnology trades.
Common insulative materials used in the electrotechnology trades include:
1. PVC (Polyvinyl Chloride) – widely used for cable insulation and conduit
2. Rubber – used in flexible cables and protective gloves
3. XLPE (Cross-Linked Polyethylene) – used in high-voltage cables for thermal and chemical resistance
4. Ceramics – used in insulators for power lines and heating elements
5. Glass – used in high-voltage insulators and specialized electronics
6. Bakelite – used in old-style switchboards and components
7. Fiberglass – used for insulating panels and enclosures
8. Paper (oil-impregnated) – used in older transformers and capacitors
9. Teflon (PTFE) – used in high-temperature, chemical-resistant wiring
Name two effects that always occur when a current is passed through a conductor.
Heat and a magnetic field.
Under what special conditions can an electrical insulator become a conductor?
An electrical insulator can become a conductor under special conditions, such as:
1. High Voltage (Breakdown Voltage) – If the voltage is high enough, it can force electrons free, causing the material to conduct electricity (called dielectric breakdown).
• Example: Air becoming conductive during a lightning strike.
2. High Temperature – Heating some insulators can provide enough energy to free bound electrons, allowing current to flow.
• Example: Glass becomes slightly conductive at very high temperatures.
3. Physical Damage or Contamination – Cracks, moisture, or dirt on an insulator’s surface can create a conductive path.
4. Radiation Exposure – Ionizing radiation can knock electrons loose, making an insulator conductive.
5. Chemical Changes – Certain chemicals can alter the structure of insulating materials, reducing their resistance.
What is the basic unit of electrical charge (or quantity of electricity) and what is the unit symbol?
The basic unit of electrical charge is the coulomb, and its unit symbol is C.
What is the basic unit of electromotive force and what is the unit symbol?
The basic unit of electromotive force (EMF) is the volt, and its unit symbol is V.
What is the basic unit of electric current flow and what is the unit symbol?
Ampere - A
What is the basic unit of electromotive force and what is the unit symbol?
Volts. - V
