Circuit Analysis (Unit -3), Introduction to AC

         Introduction to AC of Circuit Analysis

• AC stands for alternating current. 

• The AC power source produces potential that varies with time. 

• Creation of AC waves 

1. The electromechanical alternator produces voltage which switches polarity after fixed intervals of time. 
2. When it is represented on a graph, it looks like a sine wave

• Concept of Frequency and Period

1. The horizontal axis of the graph representing AC waves is marked with time and the dimension marked with one cycle of time is measured as period. 
2. Another measurement that can be taken is the back and forth oscillation of the wave called frequency. 
3. Period and Frequency are mathematical reciprocals of each other. 

• Measuring AC voltage and current

1.  AC voltage alters in polarity and current alters in phase. 
2. Hence, the peak of the amplitude of the wave is considered and the peak to peak value is taken.