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Alternating Voltage and Current. Alternating Current Applications: The Sine Wave Alternating Current Voltage and Current values For a Sine Wave Frequency Period Wavelength Phase Angle Alternating Current Circuits with Resistance Three Phase AC Power.
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Alternating Voltage and Current • Alternating Current Applications: • The Sine Wave • Alternating Current • Voltage and Current values For a Sine Wave • Frequency • Period • Wavelength • Phase Angle • Alternating Current Circuits with Resistance • Three Phase AC Power www.kashifpaf.greatnow.com
Alternating Current Applications www.kashifpaf.greatnow.com
Values in A Sine Wave Algle Degrees Radians Sin Loop Voltage 0 0 0 Zero 30 /6 0.500 50% Max 45 /4 0.707 70.7% 60 /3 0.866 86.6% 90 /2 1.000 +ve Max 180 0 Zero 270 3/2 -1.000 -ve Max 360 2 0 Zero www.kashifpaf.greatnow.com
Example: A sine wave of voltage varies from zero to a max. of 100 V. How much is the voltage at the instant of 30 degree of the cycle? 45? . Sol, V = VM sin = 100 sin 30 V = 50 V V = 100sin 45= 70.7V www.kashifpaf.greatnow.com
Alternating Current www.kashifpaf.greatnow.com
Derivation of Average and RMS values for a Sine Wave Alternation www.kashifpaf.greatnow.com
Root Mean-Square, Or Effective, Value rms value = 0.707 * peak value Or Vrms = 0.707Vmax and Imax = 0.707Imax Peak = 1/0.707 * rms = 1.414 * rms Or Vmax = 1.414Vrms and Imax = 1.414Irms Peak to Peak value = 2.828 * rms value www.kashifpaf.greatnow.com
Frequency • Number of Cycles per second is the frequency in hertz units. www.kashifpaf.greatnow.com
Period The amount of time it takes to go through one cycle is called the period. With the frequency of 50 Hz, as an example, the time for one cycle is 1/50 S. T = 1/f or f = 1/T www.kashifpaf.greatnow.com
Wavelength When a periodic variation is considered with respect to distance, one cycle includes the wavelength, which is the length of one complete wave or cycle. Or The distance traveled by the wave in one cycle is the wavelength. = velocity /frequency www.kashifpaf.greatnow.com
Wavelength Cont.. • Wavelength of radio waves: Fror electromagnetic radio waves, the velocity in air or vacuum is 186,000 mi/s, which is the speed of light. • (cm) = (3 * 10 10 cm/s) / f(Hz) Wavelength of sound waves: = (1130 ft/s) / f Hz www.kashifpaf.greatnow.com
Phase Angle Is the Angular difference in time b/w corresponding values in the cycles for two waveforms of the same frequency. www.kashifpaf.greatnow.com