# 5 Basic Concepts of Electrical Engineering

In this video, you’ll learn 5 basic concepts of electrical engineering.

1. Conventional current flow vs Electron current flow
2. Resistance and Resistivity
3. Current and Voltage
4. Ideal current source and Ideal voltage source
5. Resistors in series and parallel

List of Contents

### Conventional current flow vs Electron current flow

The electrical conductors contain a large number of free electrons which can be controlled by applying a voltage source across terminals of the conductor. The electrons flow of current is based on the fact that current flows through the circuit when electrons flow from negative terminal towards the positive terminal. Whereas the conventional current flow assumes that charges flow from the positive terminal of the battery towards the negative terminal.

### Resistance and Resistivity

The resistance of the circuit is defined as its ability to control the current. Symbol R represents it and it is mathematically expressed as:
R = ρl/A
where,
R = Resistance (ohms)
ρ = Resistivity (ohm-meters)
l = length of material (m)
A = Area (m2)

The resistivity of the material is a constant physical property of material whose value depends on the type of material.

### Current and Voltage

Current is the flow of charge, whereas voltage is the potential difference which is responsible for current flow.

### Ideal Voltage source and Ideal current source

The ideal voltage source has zero internal resistance, whereas the ideal current source has infinite internal resistance. Both ideal sources provide specified voltage and current without any loading effects.

### Resistors in series and Parallel

Two or more series resistors can be solved by the formula:
Rt = R1 + R2 + … + Rn
Whereas in parallel:
1/Rt = 1/R1 + 1/R2 + … + 1/Rn