They always told me 'there is no such thing as peak to peak voltage'.
Who are they and why do they always say these things.
Peak to peak voltage:
(a) The most positive voltage minus the most negitive voltage seen within
the measurement time. This is what is normally meant by peak to peak.
(b) The most positive minus the most negitive voltage that will ever be
seen. This is what you use when designing for overvoltages etc.
(c) The range of voltage that the signal spends 90% or 99% of its time
between. This is used when refering to noise.
(d) The same as any of the above with after the removal of some low
frequency components. This is used when measuring the fur on a waveform.
RMS voltage:
You the the voltage at each instant or time square it, find the average of
the squared value and the take the squareroot. This is very hand for
rating things like lightbulbs that don't react quickly to the input
voltage.
Peak to peak current:
(the same as the above with s/voltage/current/ )
RMS current:
(See RMS voltage )
Peak to peak power:
(a) Peak to peak voltage times the peak to peak current. This is used to
get a number that impresses the uninformed.
(b) In audio amplifiers this is the power produced when the pull up
transistor first shorts, then blows open and then the pull donw transistor
does the same. This is how many audio amplifiers are rated.
(c) The peak power caused by the positive swing plus the peak power caused
by the negitive swing. This is an almost honest measure of the pulsed
output handling ability of a circuit, so it is never used.
RMS power:
(a) Take the instantanious power square it, average the squares and then
squareroot the average. This is the RMS power but no-one ever means this
when they say RMS power.
(b) Average power misnamed RMS power. This is what most people mean if
they say RMS power.
(c) A completely fictional number created in the marketing department.