AI Tutor
If you measure 8Β V8\text{ V} across a resistor and 6Β V6\text{ V} across a series inductor, your total AC supply voltage is not 14Β V14\text{ V}β€”it is exactly 10Β V10\text{ V}.
This happens because an inductor forces the voltage across itself to lead the current by 90∘90^\circ, meaning component voltages never peak at the same time.
How do we quantify an inductor's opposition to alternating current?

Inductive Reactance

Inductive reactance (XLX_L) is the opposition an inductor offers to alternating current due to its self-induced back-EMF, measured in ohms (Ξ©\Omega).
In the 1880s, electrical engineer Oliver Heaviside formalized how dynamic AC components resist current flow differently at varying frequencies.
Because an inductor opposes rapid changes in current, faster AC cycles produce a stronger opposing voltage: XL=2Ο€fL=Ο‰LX_L = 2\pi f L = \omega L
When resistance and reactance coexist in the same circuit, how do their oppositions combine?

The RL Impedance Triangle

In a series circuit, current II is identical through every component and serves as the horizontal reference vector.
Resistance RR is purely in phase with current (0∘0^\circ), while inductive reactance XLX_L points upward at +90∘+90^\circ on the complex plane.