Indepth Electrical engineering

1. What is Current? Flow or Vibration? In metals, electrical conduction happens because of free electrons (loosely bound outer electrons of atoms). When an electric field is applied (e.g., by connecting a battery or generator), these free electrons drift very slowly through the lattice. This is called drift velocity — typically a fraction of a mm/s. However, the signal (electromagnetic wave) travels through the conductor at nearly the speed of light , which makes it appear as if electricity moves instantly. 🔑 So, current is not just vibration. Electrons do drift (flow), but very slowly. At the same time, they also oscillate/vibrate due to alternating electric fields in AC circuits. Both concepts coexist: DC circuits → electrons flow slowly in one direction. AC circuits → electrons mainly vibrate back and forth about their mean positions, with almost no net displacement. 2. Why Metals Don’t “Run Out” of Electrons You raised a good point: If electrons...

Electric Bulb (Tungsten Filament Lamp): Parts, Working, and Safety Precautions The electric bulb is one of the most widely used lighting devices in households, industries, warehouses, offices, and commercial establishments. Although LED lights, CFLs, and decorative lamps are rapidly replacing traditional bulbs, the electric bulb still holds popularity due to its low cost and durability . These bulbs are also commonly known as tungsten filament lamps , since the filament inside them is made of tungsten. Working Principle of an Electric Bulb When electric current flows through the tungsten filament, it offers resistance. This resistance causes the filament to heat up to nearly 2,500°C , producing visible light along with heat. Tungsten is used because it: Has a very high melting point . Offers high resistivity . Is durable and cost-effective . Parts of an Electric Bulb An electric bulb consists of several components, each serving a critical role: Glass Bulb – Protects th...