Electric Circuit Components and Symbols

Electric Current and Its Effects

• Common electric components have designated symbols for circuit diagrams
• This textbook utilizes a specific set of symbols for electric components

Symbols of Electric Components

• Electric cell symbols include a longer line (positive terminal) and a shorter, thicker line (negative terminal)
• A battery's symbol and connections are illustrated
• '+' and '-' symbols aid in correct cell placement inside battery compartments

Representaing Circuit Components

• 'ON' and 'OFF' switch positions are represented by unique symbols
• Lines represent wires in a circuit diagram
• A battery consists of two or more cells connected together
• A combination of cells is called a battery, with the positive terminal of one cell connected to the negative terminal of the next

Electric Cell and its role

• Various devices use batteries, sometimes placing cells side by side
• A thick wire or metal strip connects the positive terminal of one cell to the negative terminal of the next

Activities with Electric Components

• A circuit diagram can be drawn using component symbols
• Whether a bulb glows depends on the switch being in the 'ON' position, creating a closed circuit
• A thin wire called a filament glows when electric current passes through it; when the bulb gets fused, it means its filament is broken

Precautions when working with Electricity

• Touching a lighted bulb connected to the mains carries burn and electric shock risks so only use electric cells otherwise it may be dangerous
• A broken filament in a bulb results in an incomplete circuit, preventing the bulb from glowing

Heating Effect of Electric Current

• An electric current heats a wire as it passes
• Devices like electric room heaters utilize this heating effect and uses an element

Factors Affecting Heat Production

• The amount of heat a wire produces depends on its material, length, and thickness
• Incandescent bulbs generate heat along with light, wasting electricity
• Fluorescent tubes, CFLs, and LED bulbs are more electricity efficient, with LED bulbs consuming less electricity for the same light intensity

Electrical Safety and Standards

• Using electricity-efficient appliances and gadgets is advisable
• The Bureau of Indian Standards assigns the ISI mark to products
• This mark assures conformity to specifications, making ISI-marked products preferable
• Fluorescent tubes and CFLs contain toxic mercury vapor

Electric Fuses and Safety

• Special materials in wires cause them to melt and break when large electric currents pass through to prevent any damage
• Electric fuses are inserted in all electrical circuits
• Fuses have a maximum current limit and are safety devices against excessive current

Circuit Overload and Short Circuits

• The insulation wearing off wires causing direct contact leads to short circuits and is a cause for increased currents
• Connecting multiple devices to a single socket causes circuit overload
• Proper fuses blow off and break the circuit if current exceeds the safe limit
• Miniature circuit breakers (MCBs) are increasingly replacing fuses and automatically turn off when current is unsafe

Safe Electrical Practices

• Always use fuses with specified applications and ISI marks
• Never use just any wire or metal strip as a fuse
• Electric current has a magnetic effect

Magnetic Effect of Electric Current

• Compass needles deflect when near a current-carrying wire
• Hans Christian Oersted discovered the deflection of a compass needle by electric current
• Electric current flowing through a wire makes it behave like a magnet

Electromagnets

• Wrapping a wire around an iron nail creates an electromagnet
• Electromagnets can be very strong and lift heavy loads
• Electromagnets are used in cranes, to separate magnetic materials, and in medical applications
• An electric bell has an electromagnet

Electric Bell Operation

• An electric bell consists of a coil of wire wound on an iron piece
• When the iron strip contacts a screw, current flows, turning the coil into an electromagnet
• The electromagnet pulls the iron strip, causing a hammer to strike the bell and break the circuit
• The iron strip returns, re-completing the circuit and repeating the process

Learn about symbols for common electric components used in circuit diagrams. Understand electric cell symbols, including positive and negative terminals. Visualize 'ON' and 'OFF' switch positions and how wires are represented in circuits.