ideal capacitor: C dV = I dt

ideal inductor: L dI = V dt

resonant LC circuit: f = 1/(2 pi) sqrt (1 / LC)

conductor in a magnetic field: F = B l I, V = B l v

RC time constant tc = RC

RL time constant tc = L/R

resistance of wire R = rho l / A, rho = bulk resistivity, l = length, A = cross section area

ideal diode: I proportional to e^(qV/kT), q = charge on electron, k = Boltzman's constant, T in kelvin,

or at room temp: I roughly proportional to e^(39 V), doubles every 18mV or so, x10 every 59mV