Complete Basics of Electrical Engineering

🔌 What is Electricity? How Does Current Flow?

Let’s start simple - connect a wire to a 5V battery and a bulb. Turn on the switch, and the bulb lights up. Why? Because electrons are flowing through the wire. This electron flow is what we call electric current.

🔧 Current only flows in a closed circuit.

📏 To measure current, a multimeter is connected in series with the circuit.

 

🔋 What is Voltage?

Voltage is like pressure that pushes the current forward. At home, the phase wire carries 220V, and the neutral wire carries 0V.

✅ Voltage is measured using a multimeter connected in parallel to the circuit.

 

🔥 Resistance & Power Loss

Every metal has resistance, which causes energy loss in the form of heat. That’s why copper wires are used in home wiring-they have low resistance and heat up less.

📘 Ohm's Law:

V = I × R (Voltage = Current × Resistance)

 

🔁 Series vs. Parallel Circuits

• Series Circuit: One failure = all fail.
• Parallel Circuit: One failure doesn’t affect the rest.

🏠 That’s why home wiring is done in parallel - for safety and flexibility.

 

⚡ What is Power?

Power is calculated as:

Power = Voltage × Current

For example: 5V × 2A = 10 Watts

💡 Devices like motors are rated in Horsepower (HP).

1 HP = 746 Watts

 

🔄 Difference Between AC and DC Current

Feature	AC (Alternating Current)	DC (Direct Current)
Waveform	Sine wave (oscillating)	Straight line (constant)
Common Source	Home power supply	Batteries, Chargers
Frequency	50 Hz	0 Hz

⚠️ DC current can be more dangerous as it flows constantly without zero crossing.

 

⚙️ Understanding Power Factor & Reactive Power

You may have heard, “440 volts hit me when I touched you” - a funny Bollywood reference to three-phase power.

Let’s get real: Electric power has three parts:

• Active Power (Watts): Useful, productive power (lighting, heating)
• Reactive Power (VAR): Useless "foam" that doesn’t do real work
• Apparent Power (VA): The total power generated

🎯 Power Factor = Active Power / Apparent Power

The closer it is to 1, the better and more efficient your system is.

 

⚡ Why Do We Use Capacitor Banks?

Devices like motors (inductive loads) pull down the power factor.

So, industries install capacitor banks to balance:

• Voltage drops
• Generator load
• High electricity bills

✅ These banks cancel out reactive power and maintain system efficiency.

 

💡 Why Should You Know This?

Electricity powers your phones, fans, TVs, washing machines and more. Knowing how it works helps you:

• Stay safe
• Save electricity
• Reduce monthly bills

 

 

🧠 Final Thoughts

Whether you're an engineering student, a curious learner, or a professional, this is must-know knowledge. Electricity is everywhere-understanding how it works will empower you in daily life and technical careers.