1. EE2010 Fundamentals of Electric Circuits
Lecture 3
Basic laws of circuit theory: Ohm's law, Kirchoff's laws.

2. Developed in 1827 by Georg Simon Ohm
Ohm’s Law
Developed in 1827 by Georg Simon Ohm
Ohm’s Law explains the relationship between voltage (V or E), current (I) and resistance (R).
The current (I) flowing in a conductor is directly proportional to the applied voltage (V) and inversely proportional to its resistance (R)
V = IR
I = V/R
R = V/I

3. Ohm's law magic triangle3

4. Example:a
calculate the amount of current (I) in a circuit, given values of voltage (E) and resistance (R): 4

5. Example:b
calculate the amount of resistance (R) in a circuit, given values of voltage (E) and current (I): 5

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8. Ohm’s Law in Graphical Form
Linear relationship between current and voltage
y = mx
y is the current
x is the voltage
m is the slope

9. Ohm’s Law in Graphical Form9 6

10. Ohm’s Law

11. Ohm’s Law
Example : Calculate the unknown quantities in the following circuit.