Reactance opposes alternating current through inductance and capacitance. Reactance stores energy until quarter-cycle later, unlike heat dissipation. Reactance is measured in ohms, positive for inductive, negative for capacitive. Term "reactance" first suggested by M. Hospitalier in 1893
Alternating current (AC) reverses direction and changes magnitude continuously. AC is used for power distribution and consumer appliances. Most power circuits use sine waveform with positive half-period corresponding to current direction
First electromagnetic rotary machine built by Ányos Jedlik in 1826-27. Hippolyte Pixii created alternating current generator in 1832. Moritz Jacobi developed motor lifting 10-12 pounds at 1 foot/second in 1834
Induction motor produces torque through electromagnetic induction from stator magnetic field. No electrical connections needed to rotor. Rotor can be wound type or squirrel-cage type
Modern IQ experts estimate Tesla's IQ between 160 and 310 points. Born in 1856 to Serbian Orthodox priest and creative mother. Studied electrical engineering at Graz and Prague Polytechnic Institutes
Home power uses alternating current (AC) for efficiency. Direct current (DC) provides consistent power for appliances. AC voltage can be calculated using VAC/√(2) formula