Electricity-Circuits-and-their-Components (2).pdf/7TH CLASS SCIENCE CURIOSITY/BY K SANDEEP SWAMY
- 1. Electricity: Circuits and their Components Welcome to our exploration of electrical circuits! Just like Nihal and his classmates preparing for their trip to the Bhakra Nangal Dam, we'll discover how electricity works, flows through circuits, and powers our daily lives. By K Sandeep Swamy, M.Sc B.Ed For Online (IITJEE & NEET foundation and ACADEMIC) Classes Contact :9491878325 SUBSCRIBE SAMYANS EDUHUB Youtube Channel
- 2. Our Journey Through Electrical Concepts 1 Understanding Electricity Basics Sources and importance of electricity in our daily lives 2 Exploring Electrical Circuits Components, connections, and how circuits function 3 Conductors and Insulators Materials that allow or prevent electricity flow 4 Safety and Applications Practical uses and important safety precautions Throughout our presentation, we'll use simple examples like torchlights to understand complex electrical concepts.
- 3. Electricity in Our Daily Lives Electricity powers our homes, schools, neighborhoods, and cities. It comes from various sources: Hydroelectric power (like Bhakra Nangal Dam) Wind energy Solar power Thermal power plants While electricity is essential for modern life, it must be handled with care to avoid dangers.
- 4. Safety First: Important Caution Warning! Never conduct experiments with the power supply at home or school. Even electricity from portable generators can pose serious risks. For safe experimentation, use only batteries or cells, like those found in torchlights, wall clocks, radios, or remotes. The warning signs on electric poles and appliances remind us that electricity can be dangerous if not handled carefully.
- 5. Portable Sources of Electricity Electric Cells Small, portable sources of electrical energy used in devices like torchlights and remotes Batteries Combination of two or more electric cells connected together to provide more energy or last longer These portable power sources allow us to use electrical devices anywhere, without being connected to the main power supply.
- 6. Understanding a Torchlight What is a Torchlight? A torchlight (also called a torch or flashlight) is a portable device that produces light, commonly used to see in the dark. Components: Lamp: Produces light when turned on Switch: Controls turning the lamp on or off Electric Cells: Provide energy to make the lamp glow
- 7. How a Torchlight Works Switch Position When the switch is moved to the "on" position Connection Made The switch connects the cells to the lamp Current Flows Electricity flows from the cells through the circuit Lamp Glows The lamp receives electricity and produces light When the switch is moved back to the "off" position, the connection is broken, and the lamp stops glowing.
- 8. What is an Electrical Circuit? An electrical circuit is a complete path that allows electric current to flow from a power source (like a cell) through a device (like a lamp) and back, making the device work. For a circuit to work: It must form a complete loop Current flows from positive to negative terminal All components must be properly connected
- 9. Electric Cell: The Power Source Structure of an Electric Cell Every cell has two terminals: Positive Terminal (+): Marked with a "+" sign, usually a metal cap Negative Terminal (-): Marked with a "-" sign, usually a flat metal disc Function: The cell provides the energy needed to make devices work by allowing current to flow from the positive to the negative terminal.
- 10. Batteries: Combined Power A battery is a combination of two or more electric cells connected together to provide more energy or last longer. Connection: In a battery, the positive terminal of one cell is connected to the negative terminal of the next cell, forming a chain. Example: In a torch, two cells are placed so the positive terminal of one touches the negative terminal of the other, making the lamp glow when connected properly.
- 11. Fascinating Fact The term "battery" is often used for a single cell For example, what we call a mobile phone "battery" is technically one cell, even though we use the term battery for it.
- 12. Types of Electric Lamps 1 Incandescent Lamp Has a glass bulb with a thin wire filament inside that heats up and glows when current passes through it. Found in older torchlights, these lamps glow regardless of which terminal connects to the cell's positive or negative terminal. 2 LED Lamp Light Emitting Diode (LED) has no filament. It has two wires4one longer (positive terminal) and one shorter (negative terminal). LEDs glow only when connected correctly, with current flowing in one direction only. They are efficient and long-lasting.
- 13. Incandescent Lamp Structure Components: Glass bulb Thin filament wire inside Two thicker support wires Two terminals - one at metal case, one at metal tip How It Works: When electric current flows through the filament, it gets hot and glows, producing light.
- 14. LED Lamp Structure Components: No filament Two wires of different lengths Longer wire is positive terminal Shorter wire is negative terminal How It Works: LEDs glow only when connected correctly, with the positive terminal to the battery's positive terminal and the negative terminal to the negative terminal.
- 15. Making an Electric Lamp Glow Gather Components Electric cell/battery, incandescent lamp, cell holder, and electric wires Assemble Circuit Place cell in holder and connect wires to lamp terminals Complete Circuit Connect wires to form a complete path for current to flow Observe Lamp When circuit is complete, lamp will glow as current flows through filament
- 16. Electric Switch: Controlling Current What is an Electric Switch? A switch is a device that controls the flow of current by completing (closing) or breaking (opening) a circuit. How It Works: ON Position: The switch closes the circuit, allowing current to flow, making the lamp glow OFF Position: The switch opens the circuit, stopping the current, so the lamp doesn't glow A switch can be placed anywhere in the circuit and still control the current flow.
- 17. Circuit Diagrams: The Universal Language What is a Circuit Diagram? A circuit diagram is a drawing that uses standard symbols to represent the components of an electrical circuit, making it easy to understand how the circuit is built. Purpose: Circuit diagrams simplify complex circuits, making them easier to draw and understand globally.
- 18. Standard Circuit Symbols Component Symbol Description Electric Cell 4|+ Long line is positive, short line is negative Battery 4|+|+ Multiple cell symbols in series Bulb/Lamp · or ï Circle with cross inside or simple circle Switch 4/4 Break in line with diagonal line Wire 444 Straight line LED ·|4 Triangle with line and short line These symbols are standardized by organizations like the International Electrotechnical Commission (IEC), American National Standards Institute (ANSI), and the Institute of Electrical and Electronics Engineers (IEEE).
- 19. Conductors: Materials that Allow Current Flow What are Conductors? Materials that allow electric current to flow easily are called conductors or good conductors of electricity. Examples: Metals: copper, silver, gold, aluminum Metal objects: keys, coins, sewing needles Use in Circuits: Conductors, especially copper, are used for wires because they allow current to flow efficiently.
- 20. Insulators: Materials that Block Current What are Insulators? Materials that do not allow electric current to flow are called insulators or poor conductors of electricity. Examples: Plastic, rubber, glass, wood Cork, paper, wax, ceramics Objects: plastic scales, erasers, candles Use in Circuits: Insulators are used to cover wires, make plug tops, and switches to prevent electric shocks and ensure safety.
- 21. Testing Materials for Conductivity Conduction Tester A simple circuit with a battery, lamp, and two free wire ends can test if materials conduct electricity. Testing Process: Place material between the free wire ends If lamp glows, material is a conductor If lamp doesn't glow, material is an insulator
- 22. Importance of Both Conductors and Insulators Conductors Used in wires, switches, plugs, and sockets to carry current efficiently from source to device. Copper is widely used due to its good conductivity, lower cost, and abundant supply compared to silver or gold. Insulators Protect users from electric shocks by covering conductive parts. Essential for safety in electrical devices, preventing current from flowing where it shouldn't. Both conductors and insulators work together in electrical systems to provide efficient and safe operation.
- 23. Safety Warning: Human Body as a Conductor Important Safety Information The human body is a conductor, so electric current passing through it can cause severe injury or death. Never touch switches or plugs with wet hands Don't use electrical devices in wet areas Never handle damaged electrical equipment
- 24. Types of Electricity Direct Current (DC) Produced by batteries and cells Used in small devices like torchlights, mobile phones, and remote controls Current flows in one direction only Alternating Current (AC) Supplied from power plants to wall sockets Used for larger appliances like refrigerators, air conditioners, and washing machines Current changes direction periodically
- 25. Key Points to Remember 1 Electrical Basics An electric circuit is a complete path for current flow. Electric cells provide portable energy with positive and negative terminals. A battery combines multiple cells for more power. 2 Circuit Components Incandescent lamps have filaments that glow when heated. LEDs have no filament and only work when connected correctly. Switches control current by completing or breaking circuits. 3 Materials and Safety Conductors (metals) allow current flow while insulators (plastic, rubber) block it. The human body conducts electricity, so always handle electrical devices safely to prevent injury. Understanding these principles helps us safely use electricity in our daily lives.