Hundreds of formulas & variations: Ohm's Law/Watt's Law Resistor Color Code Series/Parallel Resistance/Inductance/Capacitance Unknown Value of Parallel Resistance/Parallel Inductance/Series Capacitance Voltage/Current Dividers Capacitive/Inductive Reactance Series/Parallel Resistive/Inductive/Capacitive Impedance - in parallel, series, and as current Peak/Peak-to-Peak/RMS/Average Sine Wave Conversion Wavelength/Frequency/Period/Velocity Delta/Wye Conversion RC/RL Time Constant dB,dBu,dBm,dBW,dBuV, dBV (with either equal or unequal impedances) VSWR Resonant ...