>Hi all,
>
>Sorry for slightly off topic - but it might be of use to others also.
>
>I need to read 4 voltages at 60Hz and I need the true RMS value. I know
>that I could use a true RMS detector/converter by Analog devices, but these
>are just too expensive - any others around in small DIP packages ?
>
>OR
>Is there some 'appropriate arrangement' of LM324 or similar opamps that
>might provide this conversion for frequencies around 50 to 60Hz ?
>
>Any ideas ?
>
>Rdgs
>
>mike
>Perth, Western Australia

Do you really need the true RMS value? It's usually only when you need to
precisely measure a waveform with a truly bizarre crest factor. If that's
what you've got to have, the classical method is to measure the heating
effect. Works DC to daylight.

Reg Neale