Student "edition" found at {csi dot journalspace dot com}.

Maybe I shouldn't have started this blog now, not with everything that's been going on.

My most recent Energy Conversion lecture was reminiscent of my Electromagnetic Theory lectures: all derivation of formulas and computations.

I even went one step further when I interpreted three graphs for the current in an R-L-C or resistor-inductor-capacitor resonance circuit.

There are, after all, four quantities that determine the behavior of the current graph of a series resonance circuit: the resistance, the inductance, the capacitance and the voltage.

Changing the ratio of the resistance and the voltage changes the value of the peak of the curve (or the maximum current) but it is still along the value of the resonant frequency. In other words, the change of the graph is vertical but not horizontal.

Horizontal change occurs when the ratio of the inductance and capacitance is changed.

Then the peak either moves to the left or to the right, but the height is the same.

There is, I showed them, a way to manipulate the values of the inductance and capacitance so that the resonant frequency does not change.

For example, the product of the inductance and the capacitance can still be one hundred, but their ratio could be one (a value of ten each), or the inductance could be greater or smaller.

I showed the students (on the chalkboard unfortunately, since all the LCD projectors were reserved for that class period) that having the ratio less than one produces the widest curve, while if the ratio is greater than one the curve is narrowest.

I gave them the way to determine the "thickness" of the curve which is what is called the bandwidth, that required deriving the two frequency values at each end, which was done using the quadratic equation, to the aversion of some students.

Knowing that inductive reactance is larger than capacitive reactance on one side of the resonant frequency and vice versa on the other made the assignment of signs for the radical in the quadratic equation easier, to separate the two frequencies.

Session 1691 is glad when they've finished all their math subjects. Class dismissed.