Engineering
Technology

Lesson 07 'මූලික විදුලි තාක්ෂණවේදය' (Basic Electrical Technology) හි ප්‍රධාන මාතෘකා:

• ⚡ Electric Current, Voltage & Resistance — SI units, symbols
• 📐 Ohm's Law (V = IR) සහ circuit problem solving
• 🔗 Kirchhoff's Current Law (KCL) & Voltage Law (KVL)
• 🔌 Series & Parallel Circuits — resistance, current, voltage calculations
• 🔄 AC & DC Current — differences, waveforms, RMS values
• 🔋 Capacitors & Inductors — charging, discharging, reactance
• 🔁 Transformer — step up/down, turns ratio, efficiency
• 💡 Electrical Power (P=VI), Energy (W=Pt), Power Factor
• ⚙️ Three-Phase Supply, Fuses, MCBs, Earthing, RCDs

Ohm's Law:

V = I × R  |  I = V/R  |  R = V/I

Kirchhoff's Current Law (KCL):

• Junction point: ΣI_in = ΣI_out (currents in = currents out)

Kirchhoff's Voltage Law (KVL):

• Closed loop: ΣV = 0 (sum of all voltages = zero)

Power & Energy:

P = V×I = I²R = V²/R  |  W = P×t

AL Tech Hub (altechhub.lk) හි Lesson 07 Downloads කොටසෙන් නොමිලේ ලබාගත හැකිය:

• 📄 Full Notes PDF — 6.8 MB, 94 pages
• 📄 Circuit Theory & Ohm's Law — 2.4 MB, 24 pages
• 📄 AC & DC Fundamentals — 2.8 MB, 28 pages
• 📄 Transformer Design Notes — 2.2 MB, 22 pages
• 📄 Electrical Safety Reference — 1.6 MB, 16 pages
• 📄 Formula Sheet — 0.6 MB, 4 pages
• 📊 Slide Deck (PPTX) — 8.8 MB, 58 slides
• 📝 Practice Q&A (DOCX), Past Papers, 🗜️ Complete Bundle (ZIP 30 MB)

DC (Direct Current) — constant direction:

• Batteries, solar cells, electronic devices
• Constant voltage, no frequency

AC (Alternating Current) — direction reverses periodically:

• Sri Lanka mains: 230V, 50Hz — RMS value used
• Easier long-distance transmission

Transformer — Turns Ratio:

N1/N2 = V1/V2 = I2/I1  |  AC only — DC transformer work නොකරයි