what is an alternating signal?

Answer 1

Without further information provided, I cannot help much, but an alternating signal is generally reffered to as a "wave" or "oscillation". It means that the signal varies it's state between posiive and negative over a certain period of time (frequency).

Answer 2

An alternating signal is one where it varies from positive to negative and back again.

The electricity in your wall sockets is a good example. It is actually a sine wave, but it goes positive for half a cycle and then back down to negative for the other half cycle.

One postive part and one negative part is called a whole cycle.

A picture of an alternating signal sine wave can be found on:

http://www.api-assembled.com/electric/tech/battery/pic1.jpg

The horizontal line in it represents zero volts (Ground). It shows one and a quarter cycles. the alternating signal first goes above the centre line (positive) for a half cycle and then bellow it (negative) for another half cycle.

I hope this helps a little?

Good luck!
Oh and the reason I equate zero volts with ground is that zero volts is usually taken as ground, particualarly when referancing an AC signal. Exceptions do exist, but would only confuse matters when trying to understand the basics of an alternating signal. Once these are understood, then the concepts are usually built on to encompass things like AC signals riding on a DC signal. Don't worry about the comment that zero volts is not ground at this stage!

Answer 3

It would be educational if TK_M were to tell us why he equates zero volts with "ground."

The two are not synonymous.