Common Laplace Transform Pairs#

Transforms of Elementary Signals#

 

\(f(t)\)

\(F(s)\)

ROC

1

\(\displaystyle \delta(t)\)

\(\displaystyle 1\)

All \(s\)

2

\(\displaystyle \delta(t-a)\)

\(\displaystyle e^{-as}\)

All \(s\)

3

\(\displaystyle u_0(t)\)

\(\displaystyle \frac{1}{s}\)

Re(\(s\)) > 0

4

\(\displaystyle -u_0(-t)\)

\(\displaystyle \frac{1}{s}\)

Re(\(s\)) < 0

5

\(\displaystyle t u_0(t)\)

\(\displaystyle \frac{1}{s^2}\)

Re(\(s\)) > 0

6

\(\displaystyle t^n u_0(t)\)

\(\displaystyle \frac{n!}{s^{n+1}}\)

Re(\(s\)) > 0

7

\(\displaystyle e^{-at}u_0(t)\)

\(\displaystyle \frac{1}{s+a}\)

Re(\(s\)) > \(-\)Re(\(a\))

8

\(\displaystyle -e^{-at}u_0(-t)\)

\(\displaystyle \frac{1}{s+a}\)

Re(\(s\))< \(-\)Re(\(a\))

9

\(\displaystyle t^n e^{-at} u_0(t)\)

\(\displaystyle \frac{n!}{(s+a)^{n+1}}\)

Re(\(s\)) > \(-\)Re(\(a\))

10

\(\displaystyle -t^n e^{-at} u_0(-t)\)

\(\displaystyle \frac{n!}{(s+a)^{n+1}}\)

Re(\(s\)) < \(-\)Re(\(a\))

11

\(\displaystyle \sin (\omega t) u_0(t)\)

\(\displaystyle \frac{\omega}{s^2 + \omega^2}\)

Re(\(s\)) > 0

12

\(\displaystyle \cos (\omega t) u_0(t)\)

\(\displaystyle \frac{s}{s^2 + \omega^2}\)

Re(\(s\)) > 0

13

\(\displaystyle e^{-at} \sin (\omega t) u_0(t)\)

\(\displaystyle \frac{\omega}{(s + a)^2 + \omega^2}\)

Re(\(s\)) > \(-\)Re(\(a\))

14

\(\displaystyle e^{-at}\cos (\omega t) u_0(t)\)

\(\displaystyle \frac{s+a}{(s+a)^2 + \omega^2}\)

Re(\(s\)) > \(-\)Re(\(a\))

See also: Wikibooks: Engineering_Tables/Laplace_Transform_Table and Laplace Transform—WolframMathworld for more complete references.