📚 Study Today – Basic Electrical

1. Difference Between AC and DC Current

AC (Alternating Current):

  • AC current changes its direction periodically.
  • It is commonly used in homes, offices and industries.
  • Example: Electricity supplied from a wall socket.

DC (Direct Current):

  • DC current flows in one direction.
  • It is commonly used in batteries and electronic circuits.
  • Example: Battery, power bank and solar panel output.
ACDC
Direction changesOne direction
Used in house supplyUsed in batteries
Example: 230V supplyExample: 12V battery

2. Wiring – Series and Parallel

Series Wiring

In series wiring, electrical components are connected one after another in a single path.

Example:
Battery → Switch → Bulb 1 → Bulb 2 → Return

  • Same current flows through all components.
  • If one component opens, the circuit can stop working.
  • Used in some simple circuits and control applications.

Parallel Wiring

In parallel wiring, components are connected across the same two points, creating separate paths for current.

  • Each load gets the supply voltage.
  • If one bulb fails, the other bulbs can continue working.
  • House wiring is generally connected in parallel.

3. Electrical Symbols and Colours

Common Electrical Symbols

  • L – Live/Phase
  • N – Neutral
  • E – Earth
  • ⏻ – Switch/Power symbol
  • 🔺/⏚ – Earth/Ground symbol
  • M – Motor
  • ~ – AC
  • ⎓ – DC

Common Wire Colours

For modern Indian installations, commonly used identification is:

  • Brown/Red – Phase (Live)
  • Blue/Black – Neutral
  • Green or Green-Yellow – Earth