I'm pushing my envelope here, but I'll try. Remember that we are all exposed to uses / applications of what we know, and I may just be in my realm and not looking at the overall definition.

On a o-scope, a square wave looks like |_| (negative going - flip it over for traditional view) and a triangular wave looks like /\ . This is due to wave-shaping circuits in the converter.

Getting pulsating DC by adding a diode to the circuit chops off either the upper or lower half of the sine wave, losing that as heat. The remaining portion is still a sine wave shape- but now with gaps in between the 'camel's humps'.

A full wave rectifier fills those gaps with what was chopped off in the other example, so now you would have a display looking much like DC (=) but with a bunch of bumps on the top (ripple from the tops of the sine waves). For a DC application, you could filter this off; the easiest way to start would be a big capacitor across the leads. On a car battery charger the ripple doesn't make a difference. On a stereo system, you would hear a hum - here in the US 60 Hz, and multiples therof.

Are we completely OT here yet?

Now, as far as the measurement - (opinion follows): Instantaneous voltage means nothing as long as it's within the safe limits for the device. Remember, we're looking at 60 times per second here. What the unit can produce on a continuous basis is what we generally are concerned with.

Last comparison - somebody else needs to jump in. You are buying a stereo. Do you want one that can produce 100 watts everywhere from 20 to 20,000 Hz (accepted range of human hearing) with less than 0.05 percent distortion with a given (limited) input signal, or one that can produce a gazillion watts - but only at one frequency and with a huge input signal, distortion not considered, and then for only a tenth of second before it smokes?
That's the difference between RMS and Peak (instantaneous measurement) for that application.

You're on the right track.

On Sun, 22 Oct 2006 06:55:50 -0600, lid wrote
(in article ):



Getting pulsating DC by adding a diode to the circuit chops off either the
upper or lower half of the sine wave, losing that as heat.

Not really, the diode is the electrical equivilent of a check valve. No
current flows back through it so no heat is generated. An ideal diode has
zero forward voltage drop and infinite reverse voltage drop but dissipates
zero energy.

However, everything doesn't work perfectly. Diodes in a large power circuit
do heat up and need to be cooled.

"Bruce" wrote in message ...
On Sun, 22 Oct 2006 06:55:50 -0600, lid
wrote
(in article ):



Getting pulsating DC by adding a diode to the circuit chops off either
the
upper or lower half of the sine wave, losing that as heat.

Not really, the diode is the electrical equivilent of a check valve. No
current flows back through it so no heat is generated. An ideal diode has
zero forward voltage drop and infinite reverse voltage drop but dissipates
zero energy.