Switching Power Supplies A - Z

Feedback Loop Analysis and Stability

Now, if we take the natural log of both sides of the equation f (x) = A × e

−x

, and use the

last of the equations in the previous equation set, we get

ln

[

f(x)

]

= ln(e

−x

) + ln (A) =−x + ln( A)

Further, if we compare this equation with the well-known standard equation of a straight line

y(x) = mx + c (where m is the slope and c is its intersection on the y-axis), we realize that,

if we plot ln f(x) on the vertical (“y”) axis instead of f(x) (x being the horizontal or “x” axis),

we will get a straight line.

In general, plotting a function on a log scale or plotting the log of a function on a linear scale

is one and the ...