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From: sidney@coed.coastal.ufl.edu
Newsgroups: sci.electronics
Subject: Re: polarity
Message-ID: <00947B34.A08BA800@COED.COASTAL.UFL.EDU>
Date: 26 Apr 91 13:50:51 GMT
References: <11864@jarthur.Claremont.EDU> <1991Apr23.152315.22825@news.larc.nasa.gov> <1991Apr24.111307.2296@dcs.simpact.com> <2226@gold.gvg.tek.com>,<1991Apr26.035007.2804716@locus.com>
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>
>  I know I'm the one who claimed that power is dissipated in capacitors a
>while back (ugh!), but I do not believe 120VRMS is 340V p-p. It is 170V p-p.
>
>-- 
The 120vrms power is 340v p-p.  The voltage equation for our 120 volt
system is 120*sin(377t).  The rms value is the square root of the integral
of the voltage squared over a full period.  For sine wave voltages this
works out to .707 * the peak voltage.  For 120vrms power this is
.707 * 170 = 120 volts.  The 170 volt peak voltage occurs on both the 
positive and negative portions of the sin wave.  Thusly the peak to peak 
voltage is 340V not 170.