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# Sketching exponentials - examples

Sketch exponentials with different time constants. Created by Willy McAllister.

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• @ "that this waveform is at risk of not making it
Current transcript segment all the way down to the final value. Before it's asked to turn up and go around the other way" why? due to the time constant?
• Yes. The time constant is slow relative to the time interval between switching events. The voltage waveform tends to look like a "sawtooth" with curved edges. With a fast time constant the voltage looks like a square wave with rounded sides and flat top/bottom.
• I didn't understand at minutes of the video. What do you mean by saying, "Before it's asked to turn up and go around the other way"
(1 vote)
• What we see here is the aqua output signal, v_c, rising toward its potential final value, 1V, but not making it. The orange input signal, v_s, transitions from 1V to 0V before the output voltage completes its exponential rise. That causes the rising waveform to reverse direction and become a falling waveform.

So what I meant by "it's asked to turn around" is that the input v_s switched states from high to low prior to the output v_c reaching its final state.
• In the second example, what would happen if we draw out more periods?

What I mean is: at `t=0.02 s`, the voltage did not make it "all the way up". Thus, since now it starts a little lower than at `t=0s`, does it mean that in the next period it would make it "all the way down", until zero at `t=0.03s`?

I'm not sure whether it would make it all the way down to zero, but my intuition says, it would for sure go a bit lower than it went at `t=0.01s`.

In that case, at the next peak (`t=0.04s`) it would be even a bit lower than it was at `t=0.02s`. And so on, the peaks would be gradually lower.

I guess there would be some limit value (maybe zero, maybe something else) to which the peaks at `k*0.02s` "converge"?

Or would, at some point the voltage "bounce" somehow and get back to `1.0 V` and the cycle start all over again?
(1 vote)
• Sorry, again is the same video as the previous, under a different title?