Principle of Electrical & Electronics Engineering
- 1. JCT College of Engineering & Technology, JCT College of Engineering & Technology, Pichanur, Coimbatore – 641 105. Pichanur, Coimbatore – 641 105. Principle of Electrical & Electronics Engineering Faculty Name : C.Prakash Designation : Asst. Professor Year/Sem : I/II Sem Dept : Mechanical 1
- 2. Basic concepts ✴ Electricity ✴ Charge ✴ Current ✴ Voltage ✴ Power and Energy 2
- 3. Electricity Physical phenomenon arising from the existence and interactions of electric charge 3
- 4. Charge Where can we observe/experience/use charge? 4
- 5. Charge Characteristic property of subatomic particles responsible for electric phenomena 1.602×10−19 C −1.602×10−19 C - + Electron Proton The unit of quantity of electric charge is coloumb (C) 1 coloumb = 6.25 × 1018 e e = elementary charge = charge of proton 5
- 6. Charge “Charged” particles exhibit forces Opposite charges attract one another Like charges repel each other - - + - Charge is the source of one of the fundamental forces in nature (others?) 6
- 7. Coulomb’s Law q1 q2 r (meters) (Newtons) F1,2 is the electrostatic force exerted on charge 1 due to the presence of charge 2 ke is the Coulomb constant ke = 8.987 x 109 N*m2 *C-2 7
- 8. Electric current Describes charge in motion, the flow of charge This phenomenon can result from moving electrons in a conductive material or moving ions in charged solutions 8
- 9. Electric current An ampere (A) is the number of electrons having a total charge of 1 C moving through a given cross section in 1 s. As defined, current flows in direction of positive charge flow 9
- 10. Electric circuit An electric circuit is an interconnection of electrical elements linked together in a closed path so that electric current may flow continuously Circuit diagrams are the standard for electrical engineers 10
- 11. Rate of flow of charge form node a to node b Rate of flow of charge form node b to node a (i = current) A direct current (dc) is a current of constant magnitude An alternating current (ac) is a current of varying magnitude and direction 11
- 12. Voltage Driving “force” of electrical current between two points Vab Vba Voltage at terminal a with respect to terminal b Voltage at terminal b with respect to terminal a Vab = -Vba Note: In a circuit, voltage is often defined relative to “ground” 12
- 13. Voltage The voltage across an element is the work (energy) required to move a unit of positive charge from the “-” terminal to the “+” terminal A volt is the potential difference (voltage) between two points when 1 joule of energy is used to move 1 coulomb of charge from one point to the other 13
- 14. Power The rate at which energy is converted or work is performed A watt results when 1 joule of energy is converted or used in 1 second 14
Editor's Notes
- #11: AC = alternating current, not to be confused with air conditioner