Welcome back. So far we have finished Modules 1, 2, and
3, and we're starting Module 4 on Frequency Analysis.
Previously, I've tried to show you the difference between Resistive and Reactive
Circuits, so you, to motivate you why we would want to study both of those
circuits. Last time, I showed this plot.
I showed the response of the resisted circuit to a square wave.
Now, this shows a physical circuit. This is a screenshot from an oscilloscope
and this is a resistive network. The voltage source is a sign wave and the
response across any of the resistors is also a sign wave.
Now, both of these measure voltage versus time.
Notice that the zero crossings, right here, the zero crossings all line up and
that's typical with resistant circuits. If I bring up a reactive circuit, so the
voltage source is in green and the response across any of the elements in
that circuit is in blue. Notice how there is a lag in this.
The response does not exactly line up with the input and that's typical of a
reactive circuit. And it also makes it a lot more
interesting and useful when we want to do practical applications like filtering.
So the basic concept I want you to understand in here is that if I put in a
sign wave to a circuit, whether a linear, whether a resistant circuit or reactive
circuit, I'm going to get a sign wave out.
With the reactive circuits, there's going to be a time delay, or lag in the
circuit. In both cases, the output might change
the amplitude, so there might be a git different in the amplitude from the input
to the output of this circuit. And then again in the reactive circuit,
there's also a time delay. Going back to our concept map on
frequency analysis. We will be pulling forward, the ideas and
analysis that we've already performed for RC and RLC circuits from the reactive
circuit module from the resistive circuit module.
We're going back to those methods to obtain circuit equations, so those same
tools, those strategies. The KCL, the KVL, the mesh, node, and
Thevenin equivalents, we will again use in frequency analysis.
The particular topics that will cover are going to include an introduction to
frequency domain, impedances, which are simply complex resistances, AC circuit
analysis Transfer functions, frequency response with the application to
filtering.