Basic Electrical and Electronic Principles

1. Ohm's Law

Ohm's Law is a fundamental principle in electrical engineering that describes the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. The law is expressed mathematically as:

V = I × R

Where:

V is the voltage across the conductor, measured in volts (V).
I is the current through the conductor, measured in amperes (A).
R is the resistance of the conductor, measured in ohms (Ω).

Example: If a circuit has a voltage of 12V and a resistance of 4Ω, the current can be calculated as:

I = V / R = 12V / 4Ω = 3A

2. Kirchhoff's Laws

Kirchhoff's Laws are essential for analyzing complex electrical circuits. There are two laws:

2.1 Kirchhoff's Current Law (KCL)

Kirchhoff's Current Law states that the sum of all currents entering a node (or a junction) in an electrical circuit is equal to the sum of all currents leaving that node. Mathematically, it can be expressed as:

ΣI_in = ΣI_out

Example: In a circuit where three wires meet at a junction, if currents I₁ = 5A and I₂ = 3A are entering the junction, and I₃ is leaving, then:

I₁ + I₂ = I₃ ⇒ 5A + 3A = I₃ ⇒ I₃ = 8A

2.2 Kirchhoff's Voltage Law (KVL)

Kirchhoff's Voltage Law states that the sum of all voltages around a closed loop in an electrical circuit is equal to zero. Mathematically, it can be expressed as:

ΣV = 0

Example: In a closed loop with three voltage sources V₁ = 10V, V₂ = -5V, and V₃ = 3V, the sum of voltages is:

V₁ + V₂ + V₃ = 10V - 5V + 3V = 8V

Since the sum is not zero, there must be an error in the circuit analysis or measurement.