Sketches From The Powers

1. Feb 18, 2014

Duave

1. The problem statement, all variables and given/known data

#1 Sketch the total source Voltage as a function of time for -∞ < t < +∞
#2 Sketch I(t) for -∞ < t < +∞
#3 Sketch VL for -∞ < t < +∞

2. Relevant equations

In the circuit, there exist a step source, and a constant source. I couldn't find any examples on the web to refer to when plotting graphs for these double source circuits.

So, I don't have any relevant equations.

3. The attempt at a solution

The simple inductor circuit has been uploaded along with a sketch that attempts to answer #2, and one that attempts to answer #3. I don't know how to sketch for #1.

The uploaded photo for #2 has a vertical i axes, and the uploaded photo for #3 has a VL axes.

Are these curves satisfying the sketch request?
What curve could describe #1 well?

Last edited: Feb 22, 2014
2. Feb 18, 2014

Staff: Mentor

It would appear that the total source voltage consists of the sum of the two voltage sources shown in your diagram. Only one of them changes value at time t = 0. So, what should be the value of the total source voltage for times less than zero? How might this affect your your plots?

3. Feb 18, 2014

Duave

Could this be the plot for the source voltage (the one at the bottom in the illustration). The combination of a step and curve?

Last edited: Feb 22, 2014
4. Feb 18, 2014

Staff: Mentor

No, both voltages sources should be considered as ideal sources, so they will be rigorous in their adherence to potential difference. What that means is, the source Vo will have value Vo for all time, while the source VsU(t) will go from 0V to Vs volts at t=0. They are ideal, so nothing can make them take on anything but fixed potential differences --- i.e., no curves! Straight horizontal lines only for the total source voltage....