Physics electric circuits
- 1. PHYSICS ELECTRIC CIRCUIT Teacher: Telman Askeraliyev, MSc, Italy
- 3. DESCRIPTION This lesson introduces the topic of electricity in general, and its practical applications. It includes the concepts of electric current and its unit, electric circuits, and schematic diagrams for circuit elements, and distinguishes between open circuits, closed circuits, and short circuits.
- 4. OBJECTIVES Define electric current. Identify the electric symbols for basic circuit elements. Identify and construct open, closed, and short circuits.
- 5. WHAT IS ELECTRICITY? Electricity is the flow of electric charges, typically through wires, conductors, and electrical devices. Sometimes we can see the effects of electricity in nature.
- 6. HOW DO WE MEASURE ELECTRIC CURRENT? Electric current is measured using an ammeter or, more commonly, a digital multimeter. Current sensors provide an additional way to measure current.
- 7. MULTIMETER A useful meter is a multimeter, which can measure voltage or current, and sometimes resistance. To measure voltage, the meter’s probes are touched to two places in a circuit or across a battery.
- 9. ELECTRIC CIRCUITS An electric circuit is a set of conductors (like wires) and components (like resistors, lights, etc.) connected to an electrical voltage source (like a cell or a battery) in such a way that current can flow in complete loops. Here are two circuits consisting of cells, resistors, and wires. Note current flowing from (+) to (-) in each circuit. solder joints single-loop circuit triple-loop circuit
- 10. SYMBOLS USED FOR DIAGRAMMING Wire Bulb Battery Switch
- 11. CIRCUIT IS NOT ONLY wires and devices built by people Nerves in body are an electric current connection between muscles and the brain Tail of the electric eel moves current when doing the “work” of stunning a fish it shocks Earth makes a giant circuit when lightning carries current between the clouds and the ground.
- 12. ELECTRIC CURRENT Electric current is caused by moving electric charge. Electric current comes from the motion of electrons.
- 13. OPEN VS CLOSED Current only flows when there is a complete and unbroken path, or a closed circuit. Flipping a switch to the “off” position creates an open circuit by making a break in the wire.
- 14. EXAMPLE
- 15. EXAMPLE
- 16. BATTERIES A battery uses stored chemical energy to create the voltage difference. Three 1.5-volt batteries can be stacked to make a total voltage of 4.5 volts in a flashlight.
- 17. SHORT CIRCUITS Each circuit has its own fuse or circuit breaker that stops the current if it exceeds the safe amount, usually 15 or 20 amps If you turn on too many appliances in one circuit at the same time, the circuit breaker or fuse cuts off the current. To restore the current, you must FIRST disconnect some or all of the appliances.
- 18. SHORT CIRCUITS
- 19. SHORT CIRCUITS
- 20. FUSE Fuse - small metallic strip that melts when current becomes too high. → Replacement necessary when melted
- 21. CIRCUIT BREAKER Circuit breaker - device that triggers a switch to open circuit when current is too high → reset switch when opened Both are specially designed for specific amounts of current
- 22. CIRCUIT BREAKER Circuit breakers and fuses are two kinds of devices that protect circuits from too much current by making a break that stops the current.
- 23. COMPARISON
- 24. QUIZ 1 Draw schematic diagram
- 25. QUIZ 2 Draw schematic diagram
- 26. QUIZ 2
- 28. THANK YOU!