# Signal & Systems

## Main Question or Discussion Point

what does the classification of a signal into energy or power mean, can someone plz explain the physical meaning of this, not just mathematical formulas.

Related Electrical Engineering News on Phys.org
berkeman
Mentor

i also had the same question in my mind. we are generally asked tell whether the given signal is power signal or energy signal. What excatly do we mean by this. That this signal contains power information and this signal contains energy information or something else. Can someone please clarify.

Averagesupernova
Gold Member
As defined at www.dictionary.com:
Power:
The rate at which work is done, expressed as the amount of work per unit time and commonly measured in units such as the watt and horsepower.
.
.
Energy:
The capacity of a physical system to do work.
.
Off the top of my head I'd say there is no such thing as an energy signal unless you consider the AC voltage coming into our houses an energy signal. That really isn't considered a signal either. A signal is usually is defined as something that is conveying intelligence such as audio. I wonder what the audio and video are called on pro wrestling TV? I can't consider it intelligent, so is it a signal? :rofl:
A power signal I would say is a voltage on a conductor that is carrying or capable of carrying (source included, such as an output transistor) enough current to drive a loudspeaker for instance or driving some other type of transducer.

Last edited:
Last edited by a moderator:
I don't really know what you're asking either. You can measure the power of a signal and the energy of a signal.

Maxwell said:
I don't really know what you're asking either. You can measure the power of a signal and the energy of a signal.