380 likes | 394 Views
Learn to compute circuit impedance, analyze RLC circuit response to frequency changes, and determine voltages using voltage divider formula. Explore parallel circuits and current division. Practice frequency domain analysis and waveform transformations.
E N D
Lecture 04:AC SERIES/PARALLEL CIRCUITS, VOLTAGE/CURRENT DIVIDER
OBJECTIVES • Compute the total circuit impedance for series RLC circuits. • Explain the effects of frequency changes on RLC circuit response. • Determine circuit voltages and currents in series RLC circuits. • Compute voltage drops across components in an RLC circuit using the voltage divider formula.
(a) Find total impedance • The circuit given is already in freq domain:
(b) Draw Impedance Triangle R R j q q XC ZT ZT - j
Elements in Frequency domain • =4 rad/s
(a) The current, i • The current in series circuit, • The total impedance is;
Example #3: Find iX(time domain) Solution:
Example #4: Find Z1 and Z2 Solution:
Different waveform of VS • VS1 andVS2 are different: • When analyzing ac circuit, it is expedient to express both signals as either Sine or Cosine.
Change the waveform of VS1 • Using identity:
Different waveform of VS • VS1 andVS2 are different: • When analyzing ac circuit, it is expedient to express both signals as either Sine or Cosine.
Change the waveform of VS1 • Using identity:
Elements in Frequency domain • =4 rad/s
(d) Sketch the waveform for vc(t), vL(t), ic(t), iL(t) (e) Explain the phase relationship between V and I for capacitor and inductor.
Z2 Example #7: Find ZT, IT, VC2, P
Solution • Find the total impedance: • Then, the total current is:
Solution P = VI cos (qT) = (10V)(461 mA) cos(-42.4o) = 3.40 mW
Z3 Z2 Ex: Find ZT, IL3, P
IR3, IL3, P P = EI cos (qT) = (10V)(1.01 mA) cos(31.4o) = 8.62 mW
TOOLS • Note from the previous examples, all of our tools from DC work: • Ohm’s Law • Voltage Divider • Current Divider • Kirchoff’s Current Law • Kirchoff’s Voltage Law • They are the same – but we use COMPLEX NUMBERS.