1. Alternating Current Chapter 12

2. Generating AC (12-1)

3. Armatur e

4. Positive Alternation Negative Alternation One Cycle Sine Wave

5. AC Cycle - Alternation Cycle – The complete revolution of an AC generator. Alternation – One cycle of a AC generator is made up of two alternations. Positive Alternation Negative Alternation

6. AC - Frequency Frequency – The number of cycles in a second. Hertz – The unit for frequency. Household Current – 60Hz 60Hz – 60 Cycles/second

7. Degree of Rotation

10. Amplitude Peak Time Peak to Peak Period t

11. AC Values  Amplitude – The value of the wave from zero. (- +)  Peak – The maximum value of the amplitude. (- +)  Peak to Peak – The value measured from one Peak (+) to the other Peak (-).  Period – The time of one complete sine wave. (seconds – s)  Frequency – Number of cycles per second. (hertz – Hz) f = t 1

12. AC Values Peak = Peak to Peak = Period = Frequency = 500mV 1000mV 50m s f = 0.05s 1 20 Hz

13. Effective / RMS Values Effective value of AC is the amount of AC that produces the same heating effect as an equal amount of DC. The Effective value is determined by the mathematical process call the Root Mean Square method or RMS. V rms = 0.707 V Peak

14. AC Values Effective Voltage = V rms = 0.707 V Peak V rms = 0.707 (500mV) V rms = 354 V

15. Non-Sinusoidal Wave Forms Square Wave

16. Square Wave – Pulse Width Pulse Width = ½ Period

17. Non-Sinusoidal Wave Forms

20. Fundamental Frequency The lowest frequency produced by any particular instrument is known as the fundamental frequency.

21. Harmonics Harmonics are higher frequency sine waves that are exact multiples of the fundamental frequency.

22. Volts Time(ms)