Re: LCD refresh rates - don't understand

Dave Plowman (News) wrote:

No such thing as RMS power.

Well there is - square the instantaneous power, average it and take the square root. It's not a particularly useful measure of anything though.

When people talk about "RMS power" they really mean the product of RMS voltage and current, which of course is the mean (average) power - that's the whole point of using RMS amplitude values in the first place. Amplifier "RMS power" ratings are really sine-wave mean power ratings, but this misuse of language is now so deeply entrenched that I doubt it will ever change.

So called music power was simply an ad man's dream.

ISTR that it was originally a true sine-wave mean power rating, but not a continuous rating (i.e. the o/p transistor heatsinks etc. were too small to sustain it for a long period). But by the time simple music power turned into 'PMPO' a further marketing inflation factor of 10-20 dB crept in.

There is a DIN spec for various ways of quoting power for car systems -
but I'm not sure there is one for domestic gear.

There used to be, in the era before DIN plugs gave way to phono as the standard signal interface. I've no idea whether there's a standard currently in force though.

--
Andy
.

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