13.10.2012 Views

boylistad

boylistad

boylistad

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

576 ⏐⏐⏐ THE BASIC ELEMENTS AND PHASORS<br />

dx 1<br />

dt<br />

FIG. 14.1<br />

Defining those points in a sinusoidal waveform that have maximum and<br />

minimum derivatives.<br />

x 1<br />

dx<br />

dt<br />

x<br />

0<br />

dx<br />

dt<br />

= 0<br />

max<br />

0<br />

p 2<br />

Steeper slope<br />

Higher peak<br />

Negative peak<br />

p<br />

2<br />

Sine wave<br />

dx<br />

dt = 0<br />

max<br />

dx<br />

dt = max<br />

f1 > f2 p 3 2p<br />

2 �p<br />

dx<br />

dt = 0<br />

p 3 2p<br />

2 p<br />

Cosine wave<br />

dx 2<br />

dt<br />

max<br />

x 2<br />

dx<br />

dt = 0<br />

FIG. 14.2<br />

Derivative of the sine wave of Fig. 14.1.<br />

The peak value of the cosine wave is directly related to the frequency<br />

of the original waveform. The higher the frequency, the steeper<br />

the slope at the horizontal axis and the greater the value of dx/dt, as<br />

shown in Fig. 14.3 for two different frequencies.<br />

qt<br />

Smaller negative<br />

peak<br />

FIG. 14.3<br />

Effect of frequency on the peak value of the derivative.<br />

qt<br />

�<br />

Less slope<br />

Lower peak

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!