Electricity Fundamentals
A layman-friendly series on why electricity is measured, priced, and engineered the way it is: power vs energy, watts, reactive power, AC vs DC, and power factor.
Start the course- 1
What Is Electricity, Actually?
Inside a wire, electrons drift a fraction of a millimetre per second, yet the light comes on instantly. Here is what electricity actually is: free charge, a slow drift, and an energy wave racing along near light speed.
- 2
Volts and Amps: Electrical Pressure and Flow, Explained
Voltage is electrical pressure, current is flow, and multiplying them gives you watts. The two numbers on every appliance label, explained from first principles for Malaysian 230 V supply.
- 3
What Is an Electric Circuit? Series vs Parallel
Electricity only flows in a complete loop. What an electric circuit is, why your house is wired in parallel, and what actually happens in a short.
- 4
Power vs Energy: The Difference Between kW and kWh
Power (kW) is how fast energy flows; energy (kWh) is how much flowed over time. Why the difference matters, and why your TNB bill charges for both.
- 5
Joules vs kWh: Why Energy Has Two Names
Physics has one energy unit, the joule, but your TNB bill reads in kWh, food in Calories, and petrol in megajoules. Same currency, different rulers, and why each field picked its own.
- 6
Why Is Power Measured in Watts? Blame the Steam Engine
James Watt never saw an electric grid, yet his name is on every light bulb. The story of horsepower, the watt, and why 1 hp = 746 W lets an operator compare a motor, a heater and a server on one scale.
- 7
kW, kVA and kVAR: The Power Triangle, Explained
AC power comes in three flavours: real kW does the work, reactive kVAR builds magnetic fields, and apparent kVA is what the wires carry. Here is the power triangle, power factor, and why transformers are rated in kVA.
- 8
Reactive Power Is Not Wasted Energy
Utilities penalise reactive power, but it is not energy thrown away. Here is what your motors actually do with it, and where the real waste hides.
- 9
AC vs DC: Why the Grid Alternates and Your Phone Does Not
AC reverses direction 100 times a second so it can be transformed to high voltage and travel far; DC flows one way and runs the electronics inside every device. Here is why the grid picked one and your phone the other.
- 10
How Generators Make Electricity: Spin Meets Wire
Move a magnet past a coil of wire and current flows. That one trick, discovered by Faraday in 1831, is how every kilowatt-hour Malaysia burns gets made, and why the grid runs on a sine wave.
- 11
How Transformers Work: The Grid's Quiet Machine
The machine that made the national grid possible has no moving parts. How transformers work: two coils, one iron core, a changing field, and why it only runs on AC.
- 12
The War of the Currents: Edison, Tesla and Why AC Won
The real history of the war of the currents: Edison's DC, Tesla and Westinghouse's AC, the ugly propaganda, and the physics that decided how the world gets wired.
- 13
Why 50 Hz? The Accident Behind the Grid Frequency
Malaysia runs at 50 Hz, America at 60. Neither is physics. Here is the 1890s corporate accident that set the grid frequency, and why every motor you own still obeys it.
- 14
Three-Phase Power Explained: Why Factories Get 400 V
A house gets two wires; a factory gets four. Here is why three-phase power delivers constant torque, spins motors for free, and turns 230 V into a 400 V supply.
- 15
How Electric Motors Work (and Run Everything)
Around half the world's electricity ends up spinning a motor. How electric motors work: the squirrel-cage induction motor, slip, starting surge and the nameplate.
- 16
How Electricity Meters Work: Disc to Smart Meter
The meter is the cash register of the whole electricity industry. Here is how the spinning-disc meter, the modern electronic meter, and TNB's smart meters actually measure your kWh, kW and kVARh.
- 17
How the Malaysia Electricity Grid Reaches Your Plug
Follow one kWh across the Malaysia electricity grid, from a Perak dam through 500 kV lines and substations to the 230 V at your socket. Then see why the tariff charges for peak demand and power factor, not just energy.
- 18
Electrical Harmonics: How VFDs Distort Your Power
VFDs, LED drivers, UPS and servers draw current in gulps, not smooth waves. Here is how electrical harmonics form, why they cook a balanced building's neutral, and how to measure and fix them.
- 19
Voltage Sags and Swells: Why Your Plant Trips
A voltage sag lasting a tenth of a second can stop a production line for four hours while the office lights barely flicker. Here is why sags trip plants, what causes them in Malaysia, and how to ride through.
- 20
Earthing and RCDs: Why Birds Don't Get Shocked
A bird sits on an 11,000 V line unharmed because current needs a voltage difference and a loop. That one idea explains earthing, neutral vs earth, RCDs, and why you shuffle away from a fallen line.
- 21
Rectifiers and Inverters: Electricity's Translators
The grid speaks AC; solar panels, batteries, LEDs and every chip speak DC. Rectifiers and inverters are the translators between them, and a modern building is quietly full of both. Here is how they work.
- 22
How Batteries Store Energy (and Why It Is All DC)
A battery does not store electricity; it stores chemical potential and manufactures current on demand. Why that is inherently DC, what the two datasheet ratings mean, and where storage pays off in a Malaysian building.
- 23
Power Factor Correction: What Capacitor Banks Do
How a capacitor bank supplies a motor's reactive current locally, raises power factor toward 1, and removes TNB's surcharge, plus the silent failure that brings it back.