Basic Electronics

Voltage, current, resistance and the laws that tie them. The foundation of every circuit: voltage, current, resistance and power; Ohm's and Kirchhoff's laws; systematic circuit analysis with RC, RL and AC phasors; and the network theorems that simplify complex circuits.

• Voltage — Voltage is the electrical 'push' — the energy each coulomb of charge gains or loses between two points. Learn potential difference, EMF, polarity, ground references and how real sources behave under load.
• Current — Current is the rate at which charge flows. Learn conventional vs electron flow, current density, how wires are sized, how current is measured and why a few milliamps through the body can be deadly.
• Resistance — Resistance is how strongly a material opposes current. Learn resistivity and the R = ρL/A formula, conductors vs insulators vs semiconductors, temperature coefficient, resistor types, the colour code and E-series values, tolerance, power rating, and series/parallel combinations.
• Power — Power is the rate of energy transfer. Master P = VI and its Ohm's-law forms, efficiency, power ratings, circuit loading and an introduction to AC real, reactive and apparent power.
• Ohm's & Kirchhoff's Laws — Ohm's law, Kirchhoff's current and voltage laws, and the series/parallel rules they produce. Learn to solve any resistor network with systematic nodal and mesh analysis.
• Circuit Analysis (RC, RL & AC) — Beyond DC resistor networks: capacitors and inductors store energy and make circuits time- and frequency-dependent. Learn RC and RL transients and time constants, reactance and impedance, phasors, AC analysis of RLC circuits, resonance and the first-order RC filter.
• Network Theorems — Thevenin, Norton, superposition, source transformation and maximum power transfer — the shortcuts that reduce a complex linear network to something you can reason about in one step.