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Anatomy of wave. On the Oscilloscope. Wavelength is 5.75 div. So the period is (5.75 div)*(5ms/div)=28.75 ms. P-P voltage is : (6div)*(2 v/div)=12V. 5 ms. 2 V. Phase delay between two waves. Wave A is ahead of Wave B. If we choose 0 degree for start of wave A, Wave B starts at 45 degrees.
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On the Oscilloscope Wavelength is 5.75 div. So the period is (5.75 div)*(5ms/div)=28.75 ms P-P voltage is : (6div)*(2 v/div)=12V 5 ms 2 V
Phase delay between two waves • Wave A is ahead of Wave B. • If we choose 0 degree for start of wave A, Wave B starts at 45 degrees. • Wave A is /8 (45/360=1/8) ahead of B. • You can also look at the peak positions. • Wave A peaks at 90 degrees and Wave B peaks at 135 degrees. The phase delay is 135-90=45 degrees.
Measuring delay using Oscilloscope One division • “White” wave is ahead of “blue” wave by 0.8 division (look at the peaks) • The periods (wavelength) of both waves are 5 divisions. • The delay is (0.8/5)*360=58 degrees (or 1 radian).
Another example: • Wave 1 is about 1.9 divisions ahead of wave 2. • Each wave has period of 15 divisions. • Delay is (1.9/15)*360=45 degrees.
Another example: • Wave 1 is about 3.75 divisions ahead of wave 2. • Each wave has period of 15 divisions. • Delay is (3.75/15)*360=90 degrees.
Another example: • Wave 1 is about 7.5 divisions ahead of wave 2. • Each wave has period of 15 divisions. • Delay is (7.5/15)*360=180 degrees.
R, L and C in AC circuits: • The current and voltages on a device may not be in phase.
In resistors • Current and voltage are in phase.
In capacitors: • Current is ahead of voltage
In Inductors: Voltage is ahead of current Y. Ataiiyan, PHYS42, Fall 2011