Grade 8 Technology (TECH) Summaries – Term 4 (Spot On)

This document is a summary of Grade 8 Technology, Term 4, Module 6: Electrical Systems and Control.

Key Topics Covered:

• Electrical Circuits (Unit 1): Includes input, output, process, and control devices, electrical components and their symbols, and the concept of short circuits.
• Impact of Technology and Bias in Technology (Unit 2): Covers energy in rural areas and informal settlements, energy from illegal connections, and equitable sharing of energy resources.
• Electrochemical Cells (Unit 3): Explains what electrochemical cells are, how they work, and how to make a battery using lemons.
  • Series Batteries: Increase voltage when more cells are added.
  • Parallel Batteries: Maintain the voltage of a single cell but the battery lasts longer.
• Photovoltaic Cells (Unit 4): Convert light energy into electrical energy and are also called solar cells.
  • Advantages: Use free and renewable sunlight, are clean, and are useful for rural communities.
  • Drawbacks: Are only about 20% efficient, do not produce electricity when the sun is not shining, and are currently expensive.
• Supplying Electricity to the Nation (Unit 5):
  • Generation: Discusses thermal power stations, hydroelectric power stations, pumped storage schemes, and wind-driven turbines.
  • Transmission and Distribution: Electricity is transmitted across the national grid using alternating current (AC) with the use of step-up transformers to increase voltage for long-distance efficiency and step-down transformers at substations to reduce voltage for local use. The final voltage supplied to homes is 230 V.
• Developing an Electronic Device (Unit 6): Describes the technological process for developing a device, such as a fire alarm system for a school.