1.2 Ideal and practical Voltage and current Sources.pptx

Ideal and practical Voltage and current Sources

1. DEPARTMENT OF humanities & sciences SEMESTER : I SUBJECT : BASIC ELECTRICAL ENGINEERING CHAPTER : [1] DC CIRCUITS TOPIC : [ 1.2] IDEAL AND PRACTICAL VOLTAGE AND CURRENT SOURCES PRESENTED BY: PROF. JAYARAJESH

2. Learning objective: Able to understand ideal and practical voltage sources

3. Introduction Current and Voltage Source is the Basic Components of the Electr ical and Electronic Circuit s . Current and Voltage is Most Essential Factor for the Operation of any Circuit. Before Knowing about the Current and Voltage Source we must know about the Voltage and Current.

4. CURRENT Current is Defined as the Flow of the Electric Charge.. Current is Basically Denoted by Symbol I . The Unit for the Current is A or ampere. SI Unit of Current is Coulomb/Second Measuring Element used for Current is Ammeter.

5. VOL T AGE Voltage is a Potential Difference between Two Points of an Electrical Field. It is Denoted by Symbol V The Unit for Measurement of Voltage is Volts . SI Unit for Voltage is Joule/Coulomb Measuring Element for Voltage is Voltmeter.

6. Energy Sources According to the Terminal Voltage-Current Characteristics, Electrical energy Sources are Categorized into two Parts. Voltage Source Current Source

7. VOLTAGE SOURCE The Voltage Source is a Two Terminal Element in which the Voltage is completely independent of the Current. The Representation of Voltage Source is Done by the Fig Shown Above.

8. VOLTAGE SOURCE VOLTAGE SOURCE The electrical sources are those devices that provide voltage to a circuit and their terminal voltage is completely or partially independent of current drawn from it. The purpose of the voltage source is to provide voltage rather than the current and current source is to provide current rather voltage. Theoretically, there are two types of voltage sources available in electrical networks, ideal voltage source, and practical voltage source.  

9. Different Voltage Sources

10. Facts about Voltage Source A Voltage source produces an Electromotive Force ( e.m.f. ) which causes a current to flow within a circuit Unit of e.m.f. is the volt a volt is the potential difference between two points when a joule of energy is used to move one coulomb of charge from one point to the other Real voltage sources, such as batteries have resistance associated with them In analysing circuits we use Ideal Voltage sources we also use controlled or dependent Voltage sources

11. VOLTAGE SOURCE   IDEAL voltage sources  : An imaginary voltage source, which can provide a constant voltage to load ranging from zero to infinity. Such voltage source is having zero internal  resistance , Rs and is called  Ideal Voltage Source . Practically it is not possible to build a voltage source with no internal resistance and constant voltage for that long range of the load.

12. VOLTAGE SOURCE   Practical voltage sources  always have some resistance value in series with an ideal voltage source. And because of that  series resistance , voltage drops when current passes through it. So, Practical Voltage Source has internal resistance and slightly variable voltage.

13. Current Source CURRENT SOURCE Current sources are active network elements that provide the same current to any load connected across it. The purpose of a voltage source provides current to a load rather than voltage. Ideal current sources are providing the exact same current to any resistance connected to it. Where as practical current sources may vary with resistance .

14. Current Source IDEAL CURRENT SOURCE The ideal current source provides exactly the same current to any load resistance and doesn’t change its current with changing a load resistance. Ideal current creation in a lab is not possible and they are only theoretical.

15. Current Source PRACTICAL CURRENT SOURCE Practical Current Source  has some internal resistance connected in parallel to Ideal Current Source. And some of the current flow through it and the amount of flow depends upon the load.

16. Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q 1

17. An ideal voltage source is that which has an internal resistance of Low High Zero Infinite

18. An ideal current source is that which has an internal resistance of Zero Infinite High Low

19. A practical constant voltage source should have an internal resistance ? Zero Low High Infinite

20. An ideal current source supplies the current of 200mA to load resistance of 1 k Ohm. When the load is changed to 100 ohm what will be the current 2 00m A 2 000m A 2 m A None of these

21. A practical constant voltage source should have an internal resistance ? Zero Low High infinite

22. An ideal voltage source of 12V provides a current of 150mA to a load. If the load resistance is doubled the new load current becomes 150mA 75m A 30 m A None of these

23. Learning outcomes On successful completion of the course students will be able to : Recognize the basic electrical sources-voltage and current, ideal and practical voltage and current sources

24. 24 REFERENCE S https ://www.electrical4u.com / Introductory Circuit Analysis, Robert L. Boylested, Pearson Education, Prentice Hall. Basic Electrical Engineering by Ravish R Singh, Mc Graw Hill education India( Pvt ) Limied . Basic Electrical and Electronics engineering by B.R Patil , oxford edition Networks And Systems, A Sudhakr, Shyammohan S Palli, Tata McGraw Hill, New Delhi. Network Analysis, M.E. Van Valkenburg, PHI Learning Private limited, New Delhi. Circuit Analysis Principle and Applications, Allan H. Robbins &Wilhelm C. Miller, DELMAR CENGAGE Learning, Indian Reprint .