Formula sheet
The maths bench in one place.
Core electrical, electronics, audio, radio, timing, transformer, and battery formulas with short practical notes.
Safety first, always.
ElectroLab AI teaches theory, low-voltage electronics, and planning concepts. Mains voltage, switchboards, fixed wiring, high-current systems, and legal electrical work must only be performed by licensed electricians where required.
Open Safety CenterStudy flow
Use the formula sheet to understand the relationship, then use a calculator to check the number, then measure the real low-voltage circuit on the bench.
Core electrical
Ohm's Law
V = I x R
Voltage equals current times resistance.
Current
I = V / R
Useful before powering LEDs, coils, and loads.
Power
P = V x I
Heat and ratings start here.
Resistor heat
P = I^2 x R
Choose resistor wattage with margin.
Timing and resonance
RC time constant
tau = R x C
One tau is about 63 percent of the change.
RL time constant
tau = L / R
Current mostly settles after about five tau.
RLC resonance
f = 1 / (2pi sqrt(LC))
A starting point for filters and radio tuning.
Period
T = 1 / f
Time for one cycle of a repeating waveform.
Audio, waves, and power projects
First-order crossover
f = 1 / (2pi R C)
Approximate high-pass speaker crossover point.
Wavelength
wavelength = speed / frequency
Useful for sound and radio wave thinking.
Battery runtime
hours = Ah x V x efficiency / load W
Only an estimate; batteries are messy in real life.
Transformer ratio
Vs / Vp = Ns / Np
Ideal transformer voltage ratio.