Unit 8: Alternating Current Circuits

Introduction to Unit 8

Until now we have considered electric circuits energized by steady sources (DC). However, many circuits involve time-varying electrical quantities. We consider these circuits as alternating currents (AC).  Any appliance that you plug into a wall outlet use AC, and many battery-powered devices, such as cell phones, portable radio receiver, make use of the DC supplied by the battery to crease or amplify alternating currents. This section discusses the AC. We will start with a simple series of circuits that contain resistors, capacitors, and inductors that are driven by a sinusoidal voltage. Most of the principle that we discussed in previous sections are applicable, along with several new concepts related to the circuit behavior of resistance, induction, and capacitors.

Intended Learning Outcomes

Having successfully completed this section, you should be able to

• Characterize AC circuit quantities in terms of amplitude, frequency, and phase;
• Explain the relationship between current and voltage in resistors, capacitors, and inductors, and describe these relationships using equations and phasor diagrams;
• Quantitatively describe oscillations in AC circuits;
• Determine the amount of power flowing into or out AC circuits;
• Describe the operation of transformers and power supplies.

Learning Activities

E-tivity 8.1: Read the attached handouts

E-tivity 8.2: Post any question or challenge you faced while reading the handouts. You are also invited to react on posted topics by your colleague(s) or by e-moderator(s)

E-tivity 8.3: After reading the handouts attached under this unit, attempt the questions of the quiz