2 Questions
Thursday, 12 July 2018
8:11 AM
What happens to the total impedance of a series RL circuit as the frequency is increased?








Explain why the phase angle between the generator voltage and the resistor voltage (i.e. the current) increases in magnitude (becomes a larger negative value) as the frequency is increased.
Let the frequency 𝑓0 for an RL circuit represent the frequency at which the resistance is equal to the inductive reactance, that is 𝑅𝐿=𝑋𝐿. Since 𝑋𝐿=2𝜋𝑓𝐿 for an inductor, it can easily be shown that:
Compute the frequency 𝑓0 for the circuit of Figure 7-5. What is the phase of VR with respect to VS  at this frequency?
Answer:
𝑓0=

𝜃=

A series RL circuit contains a 100 Ω resistor and a 1.0 H inductor and is operating at a frequency of 50 Hz. If 3.0 V is measured across the resistor, compute:
The current in the inductor

𝐼=
The inductive reactance

𝑋𝐿=
The voltage across the inductor

𝑉𝐿=
The source voltage

𝑉𝑆=
The phase angle between VR and VS . 

𝜃=

