1. Unit – I Basic Circuits Analysis

2. Ohm’s Law
In the period 1826 to 1827, a German physicist, Georg Simon Ohm, found the relationship between voltage, current and resistance which is referred to as Ohm’s law.

3. Ohm’s Law – Statement
Ohm’s law states that the current, I flowing in a circuit, is directly proportional to the applied voltage V at constant temperature.

4. Ohm’s Law – Understanding

5. Resistance
The resistance R of any element denotes its ability to resist (or oppose) the flow of electric current.
It is measured in ohms (Ω).
Conductors are materials which permit the flow of current. But they do resist the flow of current.

6. The resistance of a material depends on
Type of material
Length of the conductor
Cross-sectional area
Temperature
The resistance of a conductor at a given temperature is

7. Limitations of Ohm’s Law
Not applicable for varying temperature conditions.
Not all resistors obey Ohm’s law.
A resistor that obeys Ohm’s law is known as a linear resistor. A nonlinear resistor does not obey Ohm’s law.
Characteristics of linear and non linear resistor are shown below.

8. Electric Circuit

9. Classification of Circuit Elements
Circuit elements are classified into
Active elements
Passive elements
A passive element is an electrical component that does not generate power, but instead dissipates, stores, and/or releases it.
Passive elements include resistances, capacitors, and coils (also called inductors).

10. Active Elements Active elements supply power to an electrical circuit.
Example: Voltage source and current source

11. Passive Elements
A passive element either stores or dissipates the energy received from active elements.
Passive elements include resistances, capacitors, and inductors.

12. Classification of Electrical Networks
Linear and Non linear Network
Bilateral and Unilateral Network
Lumped and Distributed Network

13. Nodes, Branches and Loops

14. Laws introduced by Kirchhoff
Kirchhoff’s Laws
Gustav Robert Kirchhoff (12th March 1824 – 17th October 1887) was a German physicist.
He introduced Kirchhoff’s laws in the year 1847.
Laws introduced by Kirchhoff
Kirchhoff’s current law or point law
Kirchhoff’s voltage law or mesh law

15. Kirchhoff’s Current Law or Point Law
Kirchhoff’s first law is based on the law of conservation of charge.
Algebraic sum of currents entering a node is equal to the algebraic sum of currents leaving the same node.