AC Half Cycles: Positive vs Negative

[M.Kalai vanan]

what does the positive and negative half cycles in an ac represent?

 

[phinds]

what does the positive and negative half cycles in an ac represent?

The direction of the current. That's why it's called ALTERNATING current.

 

[skeptic2]

What does the C in AC stand for?

 

[jim hardy]

I gather you're referring to a waveform?
It's a graph of volts versus time.
Traditionally horizontal axis is time; vertical is voltage with positive up and negative down.

 

[Windadct]

Personally I never liked the "C" - because power requires voltage AND current. In AC BOTH the voltage and current change polarity - so (typically) the power is always flowing in one direction.

 

[leonalee]

what does the positive and negative half cycles in an ac represent?

Positive and negative cycles represent the direction of the alternating current.AC reverses its direction many times in a second.Number of times it changes its direction in a second is measured as frequency.Go through the Alternating current for more information..

 

[NascentOxygen]

Personally I never liked the "C" - because power requires voltage AND current. In AC BOTH the voltage and current change polarity - so (typically) the power is always flowing in one direction.

Except for the special case of the load being purely resistive, the power in AC does alternate with each positive pulse followed by a smaller negative pulse to deliver an average power that is positive.

 

[anorlunda]

Except for the special case of the load being purely resistive, the power in AC does alternate with each positive pulse followed by a smaller negative pulse to deliver an average power that is positive.

Sorry, but no. The positive and negative half cycles are the same size and there is no pulsing. When V and I are in-phase, V*I is positive when both V and I are positive, and V*I is positive when V and I are both negative. Look at the drawings in the Insight article.
https://www.physicsforums.com/insights/ac-power-analysis-part-1-basics/

 

[NascentOxygen]

Sorry, but no. The positive and negative half cycles are the same size and there is no pulsing. When V and I are in-phase, V*I is positive when both V and I are positive, and V*I is positive when V and I are both negative. Look at the drawings in the Insight article.
https://www.physicsforums.com/insights/ac-power-analysis-part-1-basics/

Maybe you didn't understand what I wrote?

That's a useful article, including this figure which neatly illustrates the general case I describe: