Solving AC problems

Example

Consider the following circuit. Calculate the phase and absolute value and the time function of the voltage named Out, when f=1MHz. The time function of the voltage generator is:

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Solution

First we find the AC transfer function,

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Then we represent the complex source and its peak value,

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The solution will be,

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where Iprbook00090000.gif0 is the desired frequency.

In our program, we first define a variable s to hold the complex frequency value, s=jIprbook00090000.gif0. Then we calculate the transfer function W(s) using the complex peak value Vsource . By default, TINA gives us the phase angle in radians. To present it in degrees, simply change the Settings/Numeric formats & precisions/Angle to DEG

With the help of the Interpreter,

s := j*2*pi*1e6

W := 1/(1+R*C*s+C*L*s^2)

VSource := 10*exp(j*pi/4) {Complex peak value of the source}

VOut := VSource*W

VAbs := Abs( VOut ) {Abs. value of the output voltage }

VFi := Arc( VOut ) {Phase value of the output voltage}

VFi=[3.9759]

VFiDeg := RadToDeg( VFi )

VAbs=[259.5747m]

VFiDeg=[227.8045]

Using these results, we write the output voltage:

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