This document provides an introduction to electricity and electric circuits. It defines electric current and how it is measured using ammeters or multimeters. It describes the basic components of electric circuits including wires, batteries, bulbs, switches and how they are represented symbolically in diagrams. It distinguishes between open circuits, closed circuits, and short circuits, explaining that current only flows in a complete closed loop. Fuses and circuit breakers are discussed as safety devices used to prevent too much current in a circuit.

1. PHYSICS
ELECTRIC CIRCUIT
Teacher: Telman Askeraliyev, MSc, Italy

2. BEAUTY OF NATURE

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.

8. COMMON CIRCUIT ELEMENTS

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

27. LESSON TAKEAWAYS!

28. THANK YOU!