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VOLT shows you the voltage, current and power on every part — but knowing the equations behind those numbers is what turns playing into understanding. Work a value out by hand, then check it against the board. If your math and the simulator agree, you've got it. If they don't, one of you is wrong — and finding out which is how you learn.
V = I × R → I = V / R → R = V / IVoltage (V, volts) = current (I, amps) × resistance (R, ohms). The single most useful equation in electronics.P = V × I = I²R = V²/RPower in watts — how fast energy is used (heat, light, motion). A part's wattage rating must beat this or it burns.R = R₁ + R₂ + R₃ …Resistances add up. The same current flows through every one.1/R = 1/R₁ + 1/R₂ … (two: R₁R₂ / (R₁+R₂))Total resistance DROPS below the smallest one. Each branch sees the same voltage.V out = V in × R₂ / (R₁ + R₂)Two resistors split a voltage. R₂ is the one you measure across. The heart of sensors, pots and references.R = (V supply − V led) / I lede.g. a red LED (≈2 V, 20 mA) on 9 V: (9−2)/0.02 = 350 Ω → use the next standard up, 360–470 Ω. Never wire an LED with no resistor — it burns out.sum to 0.Everything the battery pushes out is used up by the parts on the way back. Add the drops — they equal the supply.current in = current out.Charge doesn't pile up. What flows into a junction flows back out across its branches.Q = C × V · RC time constant: τ = R × CAfter one τ a capacitor is ~63% charged; ~5τ ≈ full. V(t) = V full × (1 − e^(−t/τ)). (VOLT's instant view is steady-state — the live charging curve is the transient scope.)τ = L / R · Reactance: X C = 1/(2πfC), X L = 2πfLReactance is "resistance" to AC: caps fight high frequencies less, inductors more.f = 1 / (2π√(LC))The frequency an L and C ring at together — the basis of every tuner, oscillator and filter.