Problem 12.1 - Average Power Delivered to an Impedance Load
*
* Use frequency-domain (phasor) analysis to hand-calculate the current
* in the given circuit. Write the time-domain expression and find the
* t=0 current to use as the initial condition in the program below.
*
* Use the SIN function and .TRAN analysis to generate PROBE graphs of
* the time-dependent voltage and current waveforms for the circuit.
*
* 1. Show the source voltage and circuit current on one graph. Note
* that you may graph either I(R1) or -I(V1) to display the current
* waveform with the correct polarity. Does the current lead or lag
* the voltage in this circuit?
*
* Use the "Zoom" feature on the PROBE menu to expand the horizontal
* axis about the mid point. When you select "Zoom" on the main menu
* and "X_zoom_in" on the next screen, the graph will be enlarged by
* a factor of two about the middle point. This gives the same result
* as changing the horizontal axis range to 25,75.
*
* Use the cursor function on the expanded graph to identify the peak
* values of the voltage and current waveforms. Determine the phase
* difference between the waveforms by converting the time difference
* to an angle measure in degrees.
*
* 2. Graph the voltage across the resistance, V(1,2). Enter the
* expression for the power delivered to the resistance, I(R1)*V(1,2).
* Observe that the instantaneous power waveform is a double frequency
* waveform that is never negative. Also enter the expression for the
* average power in the circuit, .5*100*10*COS(45/57.3). Does the
* graph of this expression agree with your expectation of what the
* term "average power" means? (Note that /57.3 converts to radians.)
*
.OPT NOPAGE NOBIAS
V1 1 0 SIN(0,100,60,0,0,135)
R1 1 2 7.0711
L1 2 0 18.756E-3 IC=??? ; Enter the initial inductance current.
.TRAN 2M .10 0 .5M UIC
.PROBE
.END