Lesson 7 - Fundamental principles of electronic engineering

• What is the structure of the atom according to the Rutherford model?

  Electrons orbiting in spheres around the nucleus
• What is the relative charge of an electron?

  -1 compared to the proton
• What is the relative mass of an electron compared to a proton?

  Negligible compared to the proton
• Why is the atom structured as it is?

  Due to attraction and repulsion forces
• What is the role of delocalized electrons in conductors?

  They allow electricity to flow easily
• How do objects conduct electricity?

  Through their chemical structure
• What is the structure of conductors?

  Metallic structure with delocalized electrons
• What happens to electrons in a conductor when a force is applied?

  They move from one side to another
• What are diodes made of?

  Two different semiconductors stuck together
• What occurs when electrons jump from Silicon-Phosphorous to Silicon-Boron?

  It produces a hole around the phosphorous
• What is the symbol for electric charge?

  Q
• What is the unit for electric charge?

  Coulomb (C)
• What does 1 Coulomb represent in terms of current?

  Charge crossing a section in 1 second at 1 ampere
• What is the formula for electric charge?

  Q = It
• What is the unit for time?

  Seconds (s)
• What is the unit for current?

  Ampere (A)
• How is current measured in a circuit?

  By placing an ammeter in series
• What does Ohm's Law state?

  V = IR
• What does a V-I graph represent?

  Relationship between voltage and current
• What does a straight line on a V-I graph indicate?

  Fixed resistance of the resistor
• What happens to the resistance if the gradient of a V-I graph changes?

  The resistance also changes
• What is the relationship between voltage and current in a series circuit?

  Total voltage is the sum of individual voltages
• How is total resistance calculated in a series circuit?

  By summing individual resistor values
• What is power defined as in electrical terms?

  Rate of energy transfer
• What is the formula for power in terms of energy?

  P = E/t
• What does the equation P = VI represent?

  Power in terms of voltage and current
• What does efficiency in electrical circuits refer to?

  Ratio of useful output to total input
• What is resistivity?

  Property that quantifies resistance in materials
• What is the formula for resistivity?

  ρ = RA/L
• What are the base units for resistivity?

  Ωm (Ohm meter)
• How is the resistance of a material calculated?

  R = ρL/A
• What does the gradient of a resistance vs. length graph indicate?

  Resistivity of the material
• What happens to power in a circuit when resistance increases?

  Power dissipated increases due to heating
• What is the relationship between power and current in a circuit?

  P = I²R or P = V²/R
• What does power dissipated in a circuit refer to?

  Energy lost due to heating components
• What is the significance of a low ohm resistor?

  It gets hotter with increased current
• What happens to current in a semiconductor diode when voltage exceeds a certain level?

  It allows current to flow as if no resistance
• What is the difference between series and parallel circuits regarding voltage?

  Voltage adds up in series circuits
• How is total current measured in a series circuit?

  It is the same at all points
• What is the relationship between voltage and current in a parallel circuit?

  Voltage is the same across all components