Ok. so back to PEP power.....so what is PEP power? Is it such a big deal?
Does it mean a whole lot? Many of us use the term PEP power, but do we
really know where it comes from and how? Well lets see if I can offer an
explaination on PEP power. First we must go back to some very fundamental
concepts. For example do we all know what the PEAK AC VOLTAGE is at our 120
volt wall socket ? OK so if you dont, I,ll tell you...its about 170 volts.
AGREE? Lets continue...So we take this wall voltage and we use a
transformer to step it up to a high value of AC voltage. Then we take that
and we usally rectify it with a full wave bridge. Now we a have a rectified
DC voltage for the plate of our linear, but what is the value of this DC
voltage? Its 1.414 times the RMS value of the secondary value of our HV
transformer. AHHH!!!
So did we create energy here? Dont think so! What about that 170 volts I
told you about before? OH...thats 1.414 times our 120 volts. Ok, so by now
we also must conclude that our voltmeters dont read PEAK AC voltage, cause if
they did, we would read 170 volts every time we measured our line voltage, So
what voltage are we really measureing? Its RMS orEFFECTIVE voltage. So we
can safely say that our 170 is Emax and our 120 is Erms. Therefore Emax=1.414
X Erms, so lets call this Epeak.
Now we are dealing with AC, so we know that if the current and voltage are in
phase, we can say the same for the current as the voltage, So Imax=1.414 X
Irms, so lets call this Ipeak. Now, is there a peak in DC voltage? No! so we
can safely say that with DC voltage or current, that Imax=Ipeak=Iaverage,
Emax=Epeak=Eaverage.....So whats the average voltage of any sine wave? Its
0, right? Ok so lets put it all together.....What is our power
formula....P=E X I Right? So if we monitor the AC voltage and current from
our power supply (remember, our meters only measure RMS voltage) with a
constant load,(such as a carrier or single tone) from our amplifier, we can
say the power our supply is giving is P=E X I Right? Yeah! but this is RMS
readings Right? What about when that AC sine wave "PEAKS" ? Now what does
our power formula become? Lets see....P=1.414(Erms) X 1.414(Irms) Right? Ok
whats next, lets simplify this (we know 1.414X1.414=2) Right? So: we can now
say the formula reads P=2(Erms) X(Irms)...Well it looks as though we just
DOUBLED our power by calculating the power at the peak values (in time) for
voltage and current. So we have just proved that PEP or PEAK is DOUBLE the
RMS value. So it is definetly true that PEP is 2 times the average DC power
in our linears! But remember that that PEAK value only happens in one very
short instant in time!
So is PEP anything to write home about? What do you think? By the way does
everybody agree with my explaination and proof of PEP equaling 2 times the DC
power concerning our linear amps? Maybe next time we will look at the
effects of reactance on antennas and what part that plays with them "WATTS"
we are sending up to it! Thanks for reading this, I just Love this amp
reflector! 73 Lou W1QJ
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