Скачать или смотреть The inductor voltage phasor and inductive reactance. [AC circuit physics]

Starting with the analysis of a simple inductor circuit, we derive the voltage phasor for the inductor and show why it leads the current phasor by pi/2.

🧠 Access full flipped physics courses with video lectures and examples at https://www.zakslabphysics.com/

Recall that a voltage phasor is a rotating vector whose horizontal projection gives the values of the sinusoidal voltage function it represents. In this video, we continue our adventure in phasor analysis of AC circuits by deriving the voltage phasor for an inductor.

To find the voltage phasor for the inductor, we analyze a simple AC inductor circuit using KVL (Kirchoff's Voltage Law) to find the equation v_L=Ldi/dt, then we sub in our standard current function i(t)=Icos(wt), take the derivative, and find that v_L(t)=omega*L*Icos(omega(t)+pi/2), in other words, the voltage phasor has an amplitude of wLI and makes an angle of pi/2 with respect to the current phasor.

We want an Ohm's Law style relation for the voltage amplitude V_L=wLI, and we see that wL is playing the role of resistance here. This is called the inductive reactance X_L=wL, and it functions as "effective resistance". Note that the inductive reactance is frequency dependent.

Finally, we view the details of the current phasor and the inductor voltage phasor and animate the rotation of the phasors to see how their horizontal projections generate the sinusoidal current and voltage functions.

This is part 2 in a short series on AC circuit physics:

Part 1: the current phasor and the voltage phasor for a resistor:
👉    • The current phasor and resistor voltage ph...  

Part 2: the voltage phasor for an inductor:
👉    • The inductor voltage phasor and inductive ...  

Part 3: the voltage phasor for a capacitor:
👉    • The capacitor voltage phasor and capacitiv...  

Part 4: phasor analysis of the RLC circuit:
👉    • RLC series circuit phasor analysis, impeda...  

Part 5: RMS values for current and voltage - full calculus derivations.
👉    • RMS values for current and voltage - full ...  

Part 6: Power calculations for inductors, capacitors and resistors.
👉    • Power in AC circuit elements - full calcul...  

Part 7: Power and the power factor in the RLC series circuit.
👉    • Power and the power factor in the series R...  

Part 8: Resonance in the RLC circuit + RLC power calculations. [TBA]

#physics #ACcircuits #phasors