05_Elec 1_2-25-2025

Principles of Electricity

• Definition: Electricity is a form of energy that occurs in natural and unusable forms such as lightning and static discharge.

• Atomic Structure: All atoms contain charged particles (positive and negative) responsible for magnetic effects, termed as electricity.

Conductors & Insulators

Conductors

• Definition: Materials that allow charged particles to flow freely.

• Examples:

  • Precious metals: gold, silver, platinum

  • Other metals: aluminum, copper

  • Water

Insulators

• Definition: Materials that prevent the flow of electricity by holding particles within their atoms.

• Examples:

  • Non-metals: plastics, glass, rubber, porcelain

Units of Measurement

Electric Current

• Unit: Ampere (A)

• Definition: Flow of electricity in a conductor.

• Analogy:

  • Voltage (V) analogous to pressure

  • Current (I) analogous to flow

  • Resistance (R) analogous to friction

Electric Potential

• Unit: Volt (V)

• Definition: Tendency (force) causing electron movement due to voltage difference.

• Conventional Current Flow: Assumed from positive (+) to negative (-).

Electric Resistance

• Unit: Ohm (Ω)

• Definition: Impedance to current flow in an electrical circuit.

• Ohm's Law: I = V/R (current is proportional to voltage and inversely proportional to resistance).

Electric Current Conversion to Heat

• Light bulb filaments have higher resistance, resulting in concentrated voltage drops, hence converting current into heat and light.

• Formula: W = A x V (Calculates power in watts).

Electric Current Types

Series Circuit

• Definition: Components connected in a single path allowing the same current to flow through all.

Parallel Circuit

• Definition: Components connected such that the same voltage is applied to each component.

Electric Current Types Continued

Direct Current (DC)

• Definition: Voltage flows in one direction (examples: batteries, solar cells).

Alternating Current (AC)

• Definition: Voltage oscillates between positive and negative.

• Frequency in the USA: 60 Hz.

• Advantage: Easily transformed voltage.

Current Distribution

Residential

• Type: Single-phase, AC

• Voltage: 120/240 volts

Large Commercial/Industrial

• Type: Three-phase, AC

• Voltage: 277/480 volts

Electricity Generation

1. Steam Turbines

• Sources: Coal-fired, gas-fired, oil-fired, nuclear plants.

2. Water Turbines

• Type: Hydro-electric dams, tidal flow plants.

3. Wind Turbines

• Example: Wind farms.

4. Photovoltaic Panels

• Converts sunlight to electricity (example: Nellis Solar Power Plant).

On-Site Electricity Generation

• Definition: Powering electric generators with internal combustion engines using natural gas, utilizing incidental heat for domestic or building heating, leading to high overall efficiency.