- #1

Machodog

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## Homework Statement

A sinusoidal voltage waveform is rectified so that it becomes a half-wave waveform (i.e. the bottom half has been "chopped off"). Determine:

i) The average p.d.

ii) The RMS p.d.

iii) The heat dissipated in a 200ohm resistor in 100s

## Homework Equations

[itex]P_{avg} = \frac{(V_{rms})^2}{R}[/itex]

## The Attempt at a Solution

I'm not sure, but I would guess that the average p.d. is the line that cuts the rectified waveform in such a way that the area above and below is the same. I have a vague recollection about it being [itex]\frac{2}{\pi}[/itex] times the peak voltage.

I am also quite uncertain about the RMS, how would the voltage being zero half the time affect this value? I'm guessing it will no longer be [itex]\frac{\sqrt2}{2} V_{peak}[/itex].

Please could anyone give me some clues on how to work out the RMS and average values?EDIT:Oops sorry I did not mean to post the same thread twice...just ignore the other one!