CONTENT6.1 Alternating Voltage andCurrents6.2 Resistor in AC Circuits6.3 Capacitor in AC circuits6.4 Inductors in AC Circuits6.5 RLC CircuitsLEARNINGOUTCOMESSolve resonance problem in RLC circuit.At the end of this lesson students should be able to:Define frequency, period, amplitude. calculate peakcurrent and voltage, power and root mean square currentand voltage.Write an equation of current and voltage at any time.Know phase relation between current and voltage for idealcomponents, RC, RL and RLC circuits.Calculate impedance and phase angle for RC,RL and RLCcircuits.
Alternating Current (AC)andDirect Current (DC)are both describe types ofcurrent flowin a circuit.InDirect current, the electric charge (current) only flows inone direction.ElectricchargeinAlternatingCurrent,ontheotherhand,changesdirectionperiodically.The voltage in AC circuits also periodically reverses because the current changesdirection with same frequency.ALTERNATING CURRENT (AC)Electric charge (current) only flows inone direction.Is an electrical current variessinusoidalinmagnitude reverse.its directionperiodicallywithsame frequency.Direct Current (DC)Alternating Current (AC)
An Alternating urrent (AC) is describes the flow of currentthat changes direction periodically.•AC is used to deliver power to houses, office buildings, etc.
Square waves are oftenused indigital andswitching electronicstotest their operation.The most common type ofAC is the sine wave. The ACin mosthomes and officeshave an oscillating voltagethat produces a sine wave.AC can come in a number of forms, as long as the voltage and current arealternating. If we plot its voltage overtime,we might see a number of differentwaveforms.Triangle waves are found insound synthesis and are usefulfor testing linear electronicslikeamplifiersSine WaveSquare WaveTriangle Wave
The number ofcomplete cycle in onecycleThe variation of current alongthe path from ABCDEThe time ( in second)taken to complete onecycleThe maximum value ofcurrent at point B and DALTERNATING CURRENTOne cyclePeriodFrequencyPeak value
EQUATION OFALTERNATING CURRENTANDALTERNATING VOLTAGEThe sinusoidal voltage can be produced by rotatinga coil with a constant angular velocity in auniform magnetic field.All function encountered in electrical engineering is produce in sinusoidalalternating.SinusoidalVOLTAGEcan beexpressed by:SinusoidalCURRENTcan beexpressed by:
A phasor is an arrow whose length represents theamplitude of an AC voltage or current.The phasor rotates counterclockwise about the originwith the angular frequency of the AC quantity.Phasor diagrams are useful in solving complex ACcircuits.ResistorCapacitorInductorPhasor Diagrams