May 25, which is one less than May 26, which is when I fly back to Norcal to see my family, where I'll give my sister a pet succulent, since we'll be celebrating her graduation from highschool, which is a monumental moment in a person's life, but perhaps exaggerated by our culture, which likes to simplify the longitudinal intricacies of life into fleeting moments, as if moments were akin to the many products that are bought, sold, and eventually thrown away...
Also, I did science today.
LAB:
Thursday, May 25, 2017
Today in Engineering
May 23
We did a thing with op amps and called it an oscillator.
We created a signal up in LabView. It looked like this: (and by LabView I meant everycircuit)
***
https://e.edim.co/56309139/kEXp1EPuizuYHWDh.pdf?response-content-disposition=filename%3D%22Day_23_AC_Op_Amps___Oscillators__AC_Power.pdf%22%3B%20filename%2A%3DUTF-8%27%27Day%252023%2520AC%2520Op%2520Amps%2520%252C%2520Oscillators%252C%2520AC%2520Power.pdf&Expires=1495829873&Signature=OBwfwA1VdpCgj4VeMXRmu-duEiJm3FcGZ1BSuhlchmR1ItRuI-VppJPWAUYKYy5DSCFQfBl0hhLxqU1ZjqKJC4QaUPUc15ErJMi3a3iW1JNqfCBSllFWlI-ueGxvzrIyoa9gQDXwg2e71foCuD8ZispgDUYfrNAGbwf81lYZc3hB03o2DRzWuE-f0NLsIJHb8VIfKvMhpEIWpdiwfwfuXgDeq-5KiYD4la7VOFBd4CxOV836sxdYy54ojS4qvIoetXviaKxlmWT9XJqr7CChxJISCsh0CmnW52TgadXGHg7LiL1SZC4seWQpbdiQjlKK-568fd4j8xRA61op-5C1Tw__&Key-Pair-Id=APKAJMSU6JYPN6FG5PBQ
LAB: Oscillators
I notice this lab is made simpler if we can use Fourier transforms on the circuit components. But I'll hold off on that.
PRELIMINARY WORK / DESIGN Design an OP AMP Relaxation Oscillator having a frequency in Hz equal to the last 3 non-zero digits of your Student ID Number (such as 274). Choose convenient values for the capacitor C and . Determine the value of R using the formula for the period T. Test your design using EveryCircuit and the model for the OP27 OP AMP.
LABORATORY PROCEDURE / RESULTS Each group member will construct the circuit that they designed and simulated. For each circuit, measure the OP AMP output voltage and the voltage across the capacitor using the oscilloscope. Record a rough sketch of the voltages in your laboratory notebook. Use the storage option to save a copy of your results for publishing in your lab report. Your lab report should include all design calculations and any necessary modifications. Be sure to comment on how well your results agreed with the theoretical calculations. If things didn’t go as they should have, explain what may have gone wrong.
We did a thing with op amps and called it an oscillator.
We created a signal up in LabView. It looked like this: (and by LabView I meant everycircuit)
***
https://e.edim.co/56309139/kEXp1EPuizuYHWDh.pdf?response-content-disposition=filename%3D%22Day_23_AC_Op_Amps___Oscillators__AC_Power.pdf%22%3B%20filename%2A%3DUTF-8%27%27Day%252023%2520AC%2520Op%2520Amps%2520%252C%2520Oscillators%252C%2520AC%2520Power.pdf&Expires=1495829873&Signature=OBwfwA1VdpCgj4VeMXRmu-duEiJm3FcGZ1BSuhlchmR1ItRuI-VppJPWAUYKYy5DSCFQfBl0hhLxqU1ZjqKJC4QaUPUc15ErJMi3a3iW1JNqfCBSllFWlI-ueGxvzrIyoa9gQDXwg2e71foCuD8ZispgDUYfrNAGbwf81lYZc3hB03o2DRzWuE-f0NLsIJHb8VIfKvMhpEIWpdiwfwfuXgDeq-5KiYD4la7VOFBd4CxOV836sxdYy54ojS4qvIoetXviaKxlmWT9XJqr7CChxJISCsh0CmnW52TgadXGHg7LiL1SZC4seWQpbdiQjlKK-568fd4j8xRA61op-5C1Tw__&Key-Pair-Id=APKAJMSU6JYPN6FG5PBQ
LAB: Oscillators
I notice this lab is made simpler if we can use Fourier transforms on the circuit components. But I'll hold off on that.
PRELIMINARY WORK / DESIGN Design an OP AMP Relaxation Oscillator having a frequency in Hz equal to the last 3 non-zero digits of your Student ID Number (such as 274). Choose convenient values for the capacitor C and . Determine the value of R using the formula for the period T. Test your design using EveryCircuit and the model for the OP27 OP AMP.
LABORATORY PROCEDURE / RESULTS Each group member will construct the circuit that they designed and simulated. For each circuit, measure the OP AMP output voltage and the voltage across the capacitor using the oscilloscope. Record a rough sketch of the voltages in your laboratory notebook. Use the storage option to save a copy of your results for publishing in your lab report. Your lab report should include all design calculations and any necessary modifications. Be sure to comment on how well your results agreed with the theoretical calculations. If things didn’t go as they should have, explain what may have gone wrong.
Phasors that aren't quite Impedance yet
May 11
(No rhyming for you today)
(Not even once, no way)
(Still not a call for help)
(Might be a call for help)
Whew, passed out there for a little bit. I hope I didn't write anything embarrassing or permanent on my blog. Oh. Oh my. Nothing to see here. Onto class things:
Sinusoids and Phasors! They exist.
I was somewhat hoping you'd stop reading up there.
Oh well.
Sinusoids can be transformed to phasors. This is a neat thing. There's a simple transform between the time and phasor domains. There's a less simple transform between the time and Laplace domains. But we can't use phasors for everything, and we can use Laplace for (just about) everything. It's a tragedy we won't get to Laplace, because the stuff I've been reading out of the textbook is gosh darn neat.
Things to remember:
Inductors voltage lead 90º
Capacitors voltage lag 90º
(Hey did you know that there's simple shortcuts to those ºspecial charactersº like these on a Mac keyboard? ¡™£¢∞§¶•ª“‘‘º ⁄€‹›fifl‡°· l This isn't a massive thing, but as far as I know it's one more reason to be smug over Windows users like prof M.)
(No rhyming for you today)
(Not even once, no way)
(Still not a call for help)
(Might be a call for help)
A sinusoid is a signal that has the form of the sine or cosine function
This is the most similar font I could find on here to Comic Sans, so the rest of the blog will be written in it, as a form of repentance for not doing the blog on time (it's a sad time writing this on a Tuesday night at 8:53pm, at least I have this glorious coffee, black liquid to warm the soul and lubricate the finger joints that I laboriously strut across this deteriorating keyboard that has served me well for so many years, not like my vagabond work ethic that leads me to abandon classes and projects like so many lost dreams of things that could be or could have been had I only put the time and commitment to them, like basket weaving, or having a relationship with my family, or speaking Spanish better)Whew, passed out there for a little bit. I hope I didn't write anything embarrassing or permanent on my blog. Oh. Oh my. Nothing to see here. Onto class things:
Sinusoids and Phasors! They exist.
I was somewhat hoping you'd stop reading up there.
Oh well.
Sinusoids can be transformed to phasors. This is a neat thing. There's a simple transform between the time and phasor domains. There's a less simple transform between the time and Laplace domains. But we can't use phasors for everything, and we can use Laplace for (just about) everything. It's a tragedy we won't get to Laplace, because the stuff I've been reading out of the textbook is gosh darn neat.
Things to remember:
Inductors voltage lead 90º
Capacitors voltage lag 90º
(Hey did you know that there's simple shortcuts to those ºspecial charactersº like these on a Mac keyboard? ¡™£¢∞§¶•ª“‘‘º ⁄€‹›fifl‡°· l This isn't a massive thing, but as far as I know it's one more reason to be smug over Windows users like prof M.)
Phinally Phasors with Impedance (And Electrolytes, what Plants Crave)
May 16, Tuesday (The day-late ides of May)
Today we denuded phasors of their complexity (yes, I just wanted to use the word denude). Today we arrived about 30 minutes late. Today we read a bit of a book I think Mason would like to read (but probably can't, he's a busy dude), called Happy City_Transforming Our Lives through Urban Design. Yes I did use an underscore to denote a subtitle. Last night we slept poorly. Tomorrow we'll sleep better. Joke's on me, as was the coffee. How much do I need to drink to get addicted? I've read that I can safely consume 500mg of caffeine a day. Think I've passed that yet? I'm on my 4th (5th?) cup of coffee today. We did some nonsense with phasors and impedance today. Luckily for me, I have a handy dandy calculator that does complex plane calculations. The world is full of these little wonders.
f.lux is conveniently turning my screen yellow to reduce blue light (which keeps you awake), and to remind to use the computer at night less. Thanx f.lux.
Impedance is actually really easy, esp. with phasors. It's like a complex resistance that changes with frequency for inductors and capacitors. We use some bold and capital letters to differentiate between the time and phasor domains with their impedances and whatnot. And that's impedance IANS.
LAB: Passive RL Circuit Response
a. Show that the amplitude gain and phase difference between the input voltage and the input current are as shown in equations (4) and (5). R b. The cutoff frequency for the circuit of Figure 2 is given to be c =. Calculate the cutoff L frequency for the circuit of Figure 2 if L = 1mH and R = 47. c. Determine the gain and phase difference for the RL circuit for frequencies co 0, co , and co =co c if L = 1mH and R = 47. d. Do your low and high frequency gain results in part (c) agree with your expectations based on the inductor’s low and high frequency behavior? (e.g. calculate the inductor impedance at low and high frequencies, substitute these impedances into the circuit of Figure 2, calculate the response of the resulting resistive circuit, and compare to the results of part (c).)
Use your function generator to apply a sinusoidal input at vIN(t). Use your oscilloscope to display both vIN(t) and vL(t). Use the oscilloscope’s math operation to display the input current, iIN(t), as provided by equation (6). Record the amplitude of vIN(t) and iIN(t) and the time delay between vIN(t) and iIN(t) for the following input voltage frequencies: = c /10 (low frequency input) = 10*c (high frequency input) = c (corner frequency input) b. Calculate the measured gains and phase differences between iIN(t) and vIN(t) for the three frequencies listed in part (b) above. Compare your measured results with your expectations from the pre-lab. Comment on your results.
a. Show that the amplitude gain and phase difference between the input voltage and the input current are as shown in equations (4) and (5). R b. The cutoff frequency for the circuit of Figure 2 is given to be c =. Calculate the cutoff L frequency for the circuit of Figure 2 if L = 1mH and R = 47. c. Determine the gain and phase difference for the RL circuit for frequencies co 0, co , and co =co c if L = 1mH and R = 47. d. Do your low and high frequency gain results in part (c) agree with your expectations based on the inductor’s low and high frequency behavior? (e.g. calculate the inductor impedance at low and high frequencies, substitute these impedances into the circuit of Figure 2, calculate the response of the resulting resistive circuit, and compare to the results of part (c).)
Use your function generator to apply a sinusoidal input at vIN(t). Use your oscilloscope to display both vIN(t) and vL(t). Use the oscilloscope’s math operation to display the input current, iIN(t), as provided by equation (6). Record the amplitude of vIN(t) and iIN(t) and the time delay between vIN(t) and iIN(t) for the following input voltage frequencies: = c /10 (low frequency input) = 10*c (high frequency input) = c (corner frequency input) b. Calculate the measured gains and phase differences between iIN(t) and vIN(t) for the three frequencies listed in part (b) above. Compare your measured results with your expectations from the pre-lab. Comment on your results.
Phase offset:
Current as function of time:
Prelab & Calculations
Circuit:
The Lessons of Yesteryear also known as Tuesday, May 9
May 9
doin fine
what's a sine
it's not a line
it's a curve
start, up it swerves
powers mah nerves
and it has mah lerve
*mic drop*
(sub-Shakespearean caliber verse courtesy of Thor's caffeinated brain)
(this isn't a call for help I swear)
So today we did a quick thing where we talked about a type of amplifier, a Schmitt Trigger, that basically gives a square wave signal on its output. The thing has hysteresis; this mean it has upper and lower thresholds at which it switches from on to off and vice versa. This is important for noise reduction.
Blah blah 2nd order circuits blah blah underdamped critically damped overdamped blah characteristic equation blah this was really fun to blah derive (no I'm serious)
IANS:
Series and Parallel Second Order Circuits, did some practice.
LAB:
RLC Circuit Response
Pre-lab:
1. Provide the differential equation governing the circuit. Attach your derivation of this differential equation . 2. Attach plots of the input step function you applied to the circuit and the resulting circuit step response. Annotate your plot to indicate the rise time, overshoot, and oscillation frequency. Provide the rise time, overshoot, and oscillation frequency . 3. Provide your estimate of the damping ratio, DC gain, and natural frequency, as determined from the step response data. 4. Compare your measured vs. expected parameters (e.g. damping ratio, natural frequency, damped natural frequency, rise time, steady state response). Where appropriate, express differences in terms of a percent of the expected value. Provide at least one reason why measured values might disagree with expectations based on your pre-lab analysis
doin fine
what's a sine
it's not a line
it's a curve
start, up it swerves
powers mah nerves
and it has mah lerve
*mic drop*
(sub-Shakespearean caliber verse courtesy of Thor's caffeinated brain)
(this isn't a call for help I swear)
So today we did a quick thing where we talked about a type of amplifier, a Schmitt Trigger, that basically gives a square wave signal on its output. The thing has hysteresis; this mean it has upper and lower thresholds at which it switches from on to off and vice versa. This is important for noise reduction.
Blah blah 2nd order circuits blah blah underdamped critically damped overdamped blah characteristic equation blah this was really fun to blah derive (no I'm serious)
IANS:
Series and Parallel Second Order Circuits, did some practice.
LAB:
RLC Circuit Response
Pre-lab:
Calculated Values:
Circuit:
1. Provide the differential equation governing the circuit. Attach your derivation of this differential equation . 2. Attach plots of the input step function you applied to the circuit and the resulting circuit step response. Annotate your plot to indicate the rise time, overshoot, and oscillation frequency. Provide the rise time, overshoot, and oscillation frequency . 3. Provide your estimate of the damping ratio, DC gain, and natural frequency, as determined from the step response data. 4. Compare your measured vs. expected parameters (e.g. damping ratio, natural frequency, damped natural frequency, rise time, steady state response). Where appropriate, express differences in terms of a percent of the expected value. Provide at least one reason why measured values might disagree with expectations based on your pre-lab analysis
Tuesday, May 9, 2017
Machine Learning Saves Forests! With Thomas Dietterich
A discussion with Thomas Dietterich of Oregon State University on how machine learning algorithms can be applied to solving problems in ecology, and how the field of machine learning has advanced since its very recent conception.
Tuesday, May 2, 2017
1 Fish 2 Fish Reactive Fish 2nd Order Reactive Circuit (Blue Fish)
2nd Order things today! The only hard part of these suckers is solving initial conditions. Everything else (damped response included is solved by a known second order equation. So we're going to do a quick review of them from my book, and then study Ideal Autotransformers instead! Autotransformers are some nifty little circuit elements with Theoretically Infinite Impedance. They're a 3 prong component, and they can be used to get large step up or step down magnitudes. I'm curious why the book didn't talk about their non-ideal maximum gain; I'm now curious whether the max would be significantly different from that of other transformer types. Ideal Transformers have no losses.
LAB: Series RLC Circuit Step Response
So we set up a Series RLC circuit with:
R = 1ohm <-- We had problems with our calculations until we realized the actual circuit resistance is ~2.5 ohms
L = 1mH
C = 100 uF
We did calculations for the predicted values of alpha, natural period, and driven period, see below.:
And our measured quantities, with appropriate calculations. See the top box for the measured quantities, and the bottom box for the predicted current response over time. The current response was generated by the math above.
And lastly, the voltage response of the capacitor over time! We used 2V Square wave driven at 2Hz, to allow plenty of time for 5*Tau to pass between Oscillations. At 2Hz, we require 5Tau to be no longer than 1/4 seconds. We show in our calculations that we expect Tau (1/alpha) to be (1/500) seconds, which is much smaller than 1/4s. It turned out that we could have gone for a significantly higher frequency input square wave, as the the circuit had realistically 1.5 additional Ohms resistance beyond the 1Ohm resistor. The effect of a higher resistance is a higher alpha, which scales inversely with Tau. Our measured Tau was .0004s, about 5 times quicker than the expected .002s expected Tau.
Pi pip Cheerio, Jesus visited me after class today, and I discovered we like many of the same shows. He might bring the new Rick and Morty card game that I've heard a little about to game night Friday! Scooooree
LAB: Series RLC Circuit Step Response
So we set up a Series RLC circuit with:
R = 1ohm <-- We had problems with our calculations until we realized the actual circuit resistance is ~2.5 ohms
L = 1mH
C = 100 uF
We did calculations for the predicted values of alpha, natural period, and driven period, see below.:
And our measured quantities, with appropriate calculations. See the top box for the measured quantities, and the bottom box for the predicted current response over time. The current response was generated by the math above.
Our vastly series RLC circuit; Wires: Yellow is square wave, Red and Orange are probes, Black is ground.
And lastly, the voltage response of the capacitor over time! We used 2V Square wave driven at 2Hz, to allow plenty of time for 5*Tau to pass between Oscillations. At 2Hz, we require 5Tau to be no longer than 1/4 seconds. We show in our calculations that we expect Tau (1/alpha) to be (1/500) seconds, which is much smaller than 1/4s. It turned out that we could have gone for a significantly higher frequency input square wave, as the the circuit had realistically 1.5 additional Ohms resistance beyond the 1Ohm resistor. The effect of a higher resistance is a higher alpha, which scales inversely with Tau. Our measured Tau was .0004s, about 5 times quicker than the expected .002s expected Tau.
Pi pip Cheerio, Jesus visited me after class today, and I discovered we like many of the same shows. He might bring the new Rick and Morty card game that I've heard a little about to game night Friday! Scooooree
Subscribe to:
Comments (Atom)