Vocational Unit 1- Basics of Electrical and Electronics PDF

Std: IX Vocational Unit 1- BASICS OF ELECTRICAL AND ELECTRONICS ENERGY  Energy is ability to do work or to cause a change.  We require energy to perform any work.  Food provides energy for humans to perform day to day activities.  Food is the main sourc...

Std: IX Vocational Unit 1- BASICS OF ELECTRICAL AND ELECTRONICS ENERGY  Energy is ability to do work or to cause a change.  We require energy to perform any work.  Food provides energy for humans to perform day to day activities.  Food is the main source of energy for us.  Energy is present everywhere in the nature in different form.  You can hear energy as sound when someone talks. You can see energy as light from sun or lamp. You can feel energy as heat when you touch hot objects. Sources of Energy  Sun  Water  Coal  Oil  Wood  Gas  Wind Types of Energy Energy Transformation “Energy can neither be created nor destroyed, it can only change from one form to another”. 1  Std: IX Chemical Energy to Mechanical Energy Chemical Energy to Electrical Energy Common Examples Different Forms of Energy  Hydel Energy- Use of water for generation of energy. Example: Dam  Thermal Energy- Use of fossil fuel (coal) for generation of energy. Eg: Power Plant  Nuclear energy - Use of nuclear reaction (uranium) for generation of energy. Example: Power Plant  Solar energy- Use of sunlight for generation of energy. Eg: Solar panel  Wind Energy – Use of wind for generation of energy. Example: Windmill  Electrical Energy Energy Conversion Energy in raw form  Process  Energy in usable form 2  Std: IX ATOMS Atom is a microscopic building block of all elements in the universe. Element is a pure substance like Oxygen, Iron, Gold, Hydrogen Atoms are extremely small, almost invisible. Number of atoms come together to form any matter. Human body is made up of more than millions of atoms. UNCOUNTABLE Structure of Atom At the center of the atom is the Nucleus. Nucleus is made up of Protons and Neutrons. Electrons spin in orbits outside the nucleus. Subatomic particles of an atom are : Proton – Positive charge (+) Neutron – Neutral (no charge) Electron – Negative charge (-) Electric Charge Charge is the property of sub-atomic particles. Opposite charges attract each other. Same charges repel each other. Charge is denoted by letter Q SI unit of charge is Coulomb One coulomb of charge is equal to 6×1018 electrons. Electrostatic Force The attractive or repulsive force between particles caused due to their charges. 3  Std: IX ELECTRICITY Types of Electricity STATIC ELECTRICITY DYNAMIC ELECTRICITY Electrical energy that occurs due to friction Electrical energy that is generated from of two objects that have different charges. source. Charges remains at fix place. Charges are moving from one place to other. Occurs for short period of time. Can be regulated continuously or at certain times. Example: Lightening Example: Household electricity  The electrons in the atom are responsible for electricity.  When force is applied, this electrons become loose and they move into another atom. This movement of electrons in same direction causes Electricity. Definition of Electricity Electricity is the flow of electrons. More the electrons more will be the electricity. ELECTRICAL QUANTITIES 1. Current 2. Voltage 3. Resistance 4. Power 4  Std: IX 1. Current (I)  Charges or electrons flowing per unit time through conductor is called electric current.  Number of electrons passing a given point in one second.  Current is measured in units called ‘amperes’, denoted by A.  1 A of current means that 1 C (One coulomb of charge = 6×1018 electrons) of charge is passing through a cross section of wire every 1 second. 𝑪𝒉𝒂𝒓𝒈𝒆 (𝑖𝑛 𝐶𝑜𝑢𝑙𝑜𝑚𝑏) Formula: 𝑪𝒖𝒓𝒓𝒆𝒏𝒕 (𝑖𝑛 𝐴𝑚𝑝𝑒𝑟𝑒𝑠) = 𝑻𝒊𝒎𝒆 (𝑖𝑛 𝑆𝑒𝑐𝑜𝑛𝑑𝑠) Types of Currents DIRECT CURRENT (DC) ALTERNATING CURRENT (AC) Electrons move only in one direction. Electrons moves in both the directions. Unidirectional in nature. Bidirectional in nature. Frequency is zero. Frequency is 50 Hertz. Example: Batteries and cells Example: AC generator 2. Voltage (V)  Voltage is electrical potential energy, per unit of charge, between two points.  The force which acts on the electrons to make them move in a certain direction is known as electromotive force or voltage.  Its unit is volt, denoted by V. (voltage is measured in volts) 5  Std: IX 3. Resistance (R)  The obstruction offered to the flow of current by conductor is called electrical Resistance.  Its unit is Ω pronounced as ‘Ohms’. 4. Power (P)  Electrical energy consumed by the appliance for a time to produce some work is called power.  The SI unit is Watt. (Power is measured in watts.) Formula: 𝑃𝑜𝑤𝑒𝑟 = 𝑉𝑜𝑙𝑡𝑎𝑔𝑒 × 𝐶𝑢𝑟𝑟𝑒𝑛𝑡 QUANTITY DENOTED BY SI UNIT Charge Q Coulombs (C) Current I Amperes (A) Resistance R Ohms (Ω) Voltage V Volts (V) Power P Watts (W) Time t Seconds (s) Direction of Electrons and Current flowing Electric current always flows from the positive side to the negative side. 6  Std: IX ELECTRIC CIRCUIT Complete path from the source to the load and back to the source is called as circuit. Path along which electricity can flow. Example of Source and Load  Source – provides energy  Load – consumes energy Simple Electric Circuit  Electric circuit provides a complete path for current to pass between two terminals of battery or source (cell). 7  Std: IX SWITCH  Switch is used in circuit to ‘turn on’ or ‘turn off’ a bulb.  Switch will simple device used to ‘open’ or ‘close’ a circuit. Open Circuit – Closed Circuit – Bulb doesn’t glow Bulb lights up If the circuit is complete, it is called as If the circuit is incomplete, it is called as Closed circuit. Open circuit. Device will receive power to work. Devices will not receive power to work. SYMBOLS To show connections or components in electrical circuit, an electrical circuit diagram is used. Circuit diagram shows how the components are connected. Every electrical component has its own symbol to represent. 8  Std: IX TYPES OF CIRCUITS 1) Series circuit  A circuit in which all components are connected as a chain and same current flows through all the components.  Current has only one path.  Voltage will differ across the components. 2) Parallel circuit A circuit is said to be parallel when the electric current has multiple (more than one) paths to flow through. The component in parallel path will have same voltage across all the ends. RESISTOR Resistor is a two-terminal electrical component that introduces electrical resistance (obstruction) in a circuit. It is used to reduce, limit or adjust the current flowing in the circuit. Circuit Using Resistors 9  Std: IX Resistance: Series circuit Resistance: Parallel circuit Resistances in circuit = R1, R2, Resistances in circuit = R1, R3 R2, R3 Total Resistance Rtotal Total Resistance Rtotal Series Circuit Parallel Circuit All components are connected in a line One or more components are connected (chain). across each other. Same current flows through all the Different current flows through each components. component. Different voltage across each component. Same voltage across each component. If one component fails or breaks, whole Even if one component fail, other circuit will fail. components will work. OHMS LAW Current through conductor is directly proportional to the applied voltage”. If voltage is increased, then the current will increase provided resistance is not changed. 𝑉𝑜𝑙𝑡𝑎𝑔𝑒 = 𝐶𝑢𝑟𝑟𝑒𝑛𝑡 × 𝑅𝑒𝑠𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑉 = 𝐼 × 𝑅 PREFIX Factor Name Symbol 109 Giga G 106 Mega M 103 Kilo k 102 Hecto h 101 Deca da 10−1 Deci d 10−2 Centi c 10−3 Milli m 10−6 Micro µ 10−9 Nano n 10