Pulse, Impulse..

[Electronman]

Hi,

Can somebody tells me what 'pulse' and 'impulse' waves are and mean in electrical circuits?
What about a wave which just have a value at zero point? What do you call it?

 

[crutschow]

A pulse has a finite duration and amplitude, and can be real or mathematical.

A true impulse is a mathematical function only, with a finite amplitude but zero width. Its typical use is to derive the transfer function of a circuit. It can sometimes be approximated in a real circuit with a very short pulse.

 

[Electronman]

Thanks,

Any graph or technical paper link?

 

[crutschow]

My math is a little rusty and my comment about an impulse function really applies to a Unit Impulse Function. One use of this is with Laplace Transforms to generate a transfer function. See https://www.math.ust.hk/~makxu/MATH151/ch06_5.ppt for a short mathematical discussion.

In practice an impulse can be viewed as a pulse applied to a system, which is so much shorter than the system response time, that the system responds as if it where a pulse with zero time but finite energy. (Think of a hammer hitting a bell).

 

[Electronman]

A graph or pic is the best I guess.
I am not able to find any link in electronics sites!

 

[Electronman]

I think impulse is a pulse limited by 0+ and 0- if makes sense?

 

[crutschow]

I think impulse is a pulse limited by 0+ and 0- if makes sense?

Not to me. 0+ and 0- what: time, voltage, energy?

 

[indulis]

The singularity functions... doublet, impulse, unit step, unit ramp and unit parabola are used in circut analysis to study circuit response to a disturbance. Integrate in one direction and differentiate in the other... i.e. take the derivative of a ramp and you get a step. Take the derivative of a step and you get an impulse (BTW… the integral of an impulse is = 1). Take the derivative of a impulse and you get a doublet. When you integrate, go in the other direction.