[Milsurplus] A Ham Radio Math Quiz

[Peter Gottlieb]

Couple of questions:

Is the resistance the same at the RF frequency mentioned?  I ask because 
you specifically mention "DC resistance."

What do you exactly mean by "power delivered to the load?"  There is 
real power and there is imaginary power.  The only real power shows up 
as heating in the resistor (or any ESR of the cap).  The current in the 
capacitor is really just imaginary power, in a simplistic sense, so 
really isn't "delivered" in terms of power despite the current.  The 
capacitor is just a conduit for the power to get to the resistor.  If 
there were no resistor and the capacitor was ideal there would be no 
power delivered to the "load" at all.

Careful here about calculations.  Peak to peak must be converted to RMS, 
then you should be able to easily figure the capacitive reactance (the 1 
over 2 pi F C equation).  Then solve the rest of the algebra.

What's the intent and application of this?

P



David Stinson wrote:
> Given: 
> A load of 100 pFd in series with 5 Ohms of DC resistance.
> An oscilliscope measures that an RF power amplifier delivers
> 100 volts of  P-T-P RF at 3870 KC across this load.
>
> 1.  What is the RF current in the load?
> 2.  What is the power delivered to the load?
>
> Show your work.
>
> 73 D.S.
>
>
>
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