This time we're talking with Professor Michel Maharbiz on the ethics of cyborg-idizing beetles to remotely perform commands with electrodes and radio signals. We get deep into how micro biology is pushing the frontiers of science in new and interestingly morally complicated ways.
Friday, June 16, 2017
Tuesday, June 13, 2017
Directions of Chemistry, with Christopher Cramer
In this episode, Professor Christopher Cramer of University of Minnesota explore recent and future developments in chemistry, broad as that may sound. We step a bit into the weeds of his research in polymer development, and talk about the potential growth of science in curricula in the United States.
Dr. Charles Ferris State of Petroleum Engineering
Petroleum Engineering has a bad rap; is it deserved? In this episode Dr. Charles Harris and I explore some of the myths behind petroleum engineering, the direction of the industry, and what the future holds for petroleum engineering.
A Chemical-filled past, present, and future, with Christopher Cramer
How often do you stop and think, I'm a massive chemical? In this episode, Professor Christopher Cramer of University of Minnesota and I explore how chemists push the boundaries of the building blocks of our existence, hopefully toward a sustainable future.
Electrodes, Ethics, and armies of remote Control Beetles, with Michel Maharbiz
A discussion of the ethics and implications of biological engineering in developing tools on the scale of nanometers to electronically control beetles, and treat cancers.
Thursday, May 25, 2017
Tomorrow in Engineering
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:
Also, I did science today.
LAB:
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
Tuesday, April 25, 2017
Not feeling rn. My mind is in Spaaaaaace. Focus in Thor. Nooooooo. It's k. Review day. We're not doing stufffffff. Mason trashes some colleges day.
Universities Mason trashed today:
UC Irvine
UNLV (engineers wanted)
Cal Poly Pomona
Harvey Mudd (just that they don't accept transfers)
Immediately out of college students "you are STILL useless out of college"
and some Cal State Schools, especially for students looking to do graduate work
Words in Spanish that I'm working on memorizing today. Fun fact, Blogger doesn't believe in tabs for some reason. Spaces all the way son
(from http://www.linguasorb.com/spanish/verbs/most-common-verbs/2)
llevar to carry/bring
llevar to carry/bring
tratar to treat/handle
recibir to recieve
conseguir to get/obtain
permitir to permit
sacar to take out/stick out
presentar to introduce
acabar to finish
traer to bring
morir to die
realizar to accomplish/achieve
lograr to get/achieve/obtain
reconocer to recognize
alcanzar to catch up/reach
dirigir to direct
utilizar to utilize
cumplir to fulfil/carry out
offrecer to offer
intentar to try/attempt
Hmm, 19. almost a perfect 20.
Ah, class begins. ~8:30
I went outside to do burpees to lower my energy level. And also to take a picture that will be shown later in the blog in memorandum of Alex's now absent mustache.
I went outside to do burpees to lower my energy level. And also to take a picture that will be shown later in the blog in memorandum of Alex's now absent mustache.
We talk about capacitors for a bit and then get on to op amp integrators and differentiators, from the end of chapter 6 if I recall.
They look like this:
Look at that beaut of a circuit. What a beaut.
There exists a differentiator. We wont be caring very much since there's a lot of noise on the output. But we will be doing a lab on the things! And boy oh boy, you get to see the noise.
Onto Chapter 7 things: Switching functions! Which the book seems to make a quick note of, use for a chapter, and then discard.
there is u for unit step, delta for unit impulse, and r for unit ramp starting at time 0.
we can use these to model 1st (and second) order circuit transient response.
We can describe a voltage source in terms of the unit step function.
Differentiator Lab:
So we're going to calculate the appropriate frequency to find a gain of one between our in and out signals on this amazing Differentiator circuit. See below graph for values, and picture for diagram and derivation of how we got to 230Hz for unity gain. Note that we went with .1 V on the input so as to reduce noise to the point where we could observe significant gains on the output.
Results, with three measurements and an r^2 correspondence between predicted and measured:
Calculations and Prelab:
Signal for 230 Hz:
Signal for 100 Hz:
Signal for 500 Hz:
Circuit with ground at pin 20, signal in at 7, and ±5V on the rails:
After I finished the lab, Prof Mason was teaching some easy 1st order equations nonsense, so I used this time to unite my face with a plant. Plant Thor felt lonely, so he invited friends:
Ciao!
Sunday, April 23, 2017
Rockets and Robots with Professor Martin Mason
In this episode, you'll hear from Professor Martin Mason of Mt. San Antonio College about his recent projects in rocket building and robotics. Stick around to hear from his robotics team about their challenges in robotics and future goals.
Tuesday, April 18, 2017
Tau-ting a circuit
Now I'm really curious what it was. The gardener said he didn't know, but that he would find out. Perhaps I'll see the plant-man again one day. *Cue dramatic mysterious plant music*
Professor Mason thought it prudent to introduce inductors today. Parallel and Series inductors, and more, what a time to be alive!
We did a bit of basic calculus on inductors. For instance, did you know that
V = L*di/dt
Well now you do. And if you do a first order circuit, where a resistor is in series with an inductor, you might find that
V(t) = V_0 * e^(t/tau) where tau = L/R. or T = 1/(RC).
This is the behavior of a first order circuit.
We did a practice circuit with 5V in series with a switch, then in parallel to a pair of resistors and a capacitor. We modeled the time behavior of the circuit. We calculated the time constant, tau, to be .015s, and 5Tau (which we will measure with an oscilloscope) to be .075s.
Alex made the circuit today:
Triggered response of RC circuit, Tau is the time difference between base and plateau, about 80ms. We ran the data and were very close to the calculated Tau. We found:
We measured the time by reading the oscilloscope, taking the difference between the trigger point and point where the voltage has about peaked. We observe 10% error, which is really good. We have to estimate the point where 5Tau is on the oscilloscope screen, which accounts for the marginal error.
LC Circuit Lab type occurence
We moved on from capacitors to inductors. Capacitors are old news, and we move on quicker than a.. hmm what's a good pop culture reference... ah, we move on quicker than United Airlines customer base after their embarrassing "gaffe" last week. Heh, I am clearly the pinnacle of wit.
Recall, inductors are the reciprocal of capacitors.
T = RC (caps) = L/R (inductors)
We did a practice example. We're going to find the value of the inductor Mason gave us based on that diagram. We're going to measure 5 Tau, and calculate backwards to find the size of the Inductor.
We adjusted our settings, and found 5 tau = 5 micro seconds. Therefore, Tau is 1 microsecond, and we can solve backwards to find the inductance. Given a 1kOhm and 2.2kOhm resistor in parallel, the equivalent resistance was 687 ohms, and we find the inductor is about .67mH. Science Bitches!
*I'm getting my energy back, definitely going running today...Caffeine is magic~*
RAGE BRIDGE
RAGEBRIDGE is the name of a motor controller. Calm down now. A large arc appears across the connector, caused by capacitive load discharging (I assume).
So we ran over capacitors in class. Not literally. We might have literally blown an electrolytic though. Woo!
Capacitors aren't so crazy. Recall from physics:
q = Cv
and
C = e_0*A/d.
This describes how to treat a capacitor in a nutshell.
There was a long treatment of what capacitors are. I'm going to instead describe what electrolytics are. Electrolytics are made of salt in solvent with aluminum electrodes. They're bigger than most capacitors, but they're fairly cheap, and have a wide range of capacitances up into the micro Farads.
One has to be careful about which lead is which, electrolytics are limited in their ability to be voltage biased in one direction.
There are some others. They're all neat. My fingers lament my not wanting to type about them.
Capacitors generally block dc, pass ac, shift phase to the right, and can be used to start motors or suppress noise. The useful thing to know:
i = C*dv/dt & v = 1/C * integral(i)dt from t_0 to t.
and the energy stored, w, which is represented as the integral from -inf to t:
w = C*integral(p=v*dv) = 1/2*C*v^2 from -inf to t.
If we note that v = q/C, then
w = q^2/(2C)
Beyond math, the important properties of a capacitor are:
A. The voltage across a cap cannot change instantaneously
B. The current across a cap at DC approaches zero
C. Ideal caps don't dissipate energy
D. non ideal capacitors may leak a little current.
We did an in-class example of how capacitors behave. Calculations:
Capacitor Voltage Lab
1. sketched cap voltage/current for all inputs
So we applied a sinusoidal frequency at 1 and 2kHz and 2V to a series RC, and then did the same with a triangular input voltage at 100Hz, 4V. See below:
2,3,4 Oscilloscope windows
We used the software's math toolbox on the scope to view both the current and the voltage. We know the current because we can calculate it as a function of the measured Voltage, and the known resistance.
2kHz sinusoidal input
1kHz sinusoidal input
Triangular 100 Hz input
Circuit with an inductor Circuit with a capacitor
We repeated the lab for inductors:
In this lab, we demonstrated the capacitor current at various AC supplies, and how reactive components shift the voltage signal out of phase. Voltage across inductors leads the resistive voltage, and capacitive voltage lags resistive voltage.
So we ran over capacitors in class. Not literally. We might have literally blown an electrolytic though. Woo!
Capacitors aren't so crazy. Recall from physics:
q = Cv
and
C = e_0*A/d.
This describes how to treat a capacitor in a nutshell.
There was a long treatment of what capacitors are. I'm going to instead describe what electrolytics are. Electrolytics are made of salt in solvent with aluminum electrodes. They're bigger than most capacitors, but they're fairly cheap, and have a wide range of capacitances up into the micro Farads.
One has to be careful about which lead is which, electrolytics are limited in their ability to be voltage biased in one direction.
There are some others. They're all neat. My fingers lament my not wanting to type about them.
Capacitors generally block dc, pass ac, shift phase to the right, and can be used to start motors or suppress noise. The useful thing to know:
i = C*dv/dt & v = 1/C * integral(i)dt from t_0 to t.
and the energy stored, w, which is represented as the integral from -inf to t:
w = C*integral(p=v*dv) = 1/2*C*v^2 from -inf to t.
If we note that v = q/C, then
w = q^2/(2C)
Beyond math, the important properties of a capacitor are:
A. The voltage across a cap cannot change instantaneously
B. The current across a cap at DC approaches zero
C. Ideal caps don't dissipate energy
D. non ideal capacitors may leak a little current.
We did an in-class example of how capacitors behave. Calculations:
Capacitor Voltage Lab
1. sketched cap voltage/current for all inputs
So we applied a sinusoidal frequency at 1 and 2kHz and 2V to a series RC, and then did the same with a triangular input voltage at 100Hz, 4V. See below:
2,3,4 Oscilloscope windows
We used the software's math toolbox on the scope to view both the current and the voltage. We know the current because we can calculate it as a function of the measured Voltage, and the known resistance.
2kHz sinusoidal input
1kHz sinusoidal input
Triangular 100 Hz input
Circuit with an inductor Circuit with a capacitor
We repeated the lab for inductors:
In this lab, we demonstrated the capacitor current at various AC supplies, and how reactive components shift the voltage signal out of phase. Voltage across inductors leads the resistive voltage, and capacitive voltage lags resistive voltage.
Come, gather round friends and Op Amps, Cascade into the future
On the day we call Tuesday, quiet it was in the room
Kevin was tired, class would start quite soon
His birthday arrived without a great ruckus
Until Thor clanked his coffee gear in among us.
I made coffee for Kevin (and the class) on his birthday. I might have put more than just coffee in. Happy 21st Kev.
Today's lecture was a simple linear continuation on the Op Amps discussing we've been having for awhile. We talked about cascaded Op Amps. Cascaded Op amps are simply a group of Op amps that stack gains multiplicatively (a devious word to spell). In contrast to that devious word, these Op amps are fairly easy.
A = A1*A2*A3
The cascade connection, it should be noted, can very easily saturate the Op Amp. Don't do that unintentionally. We did a bit of practice with this.
LAB- Part 1
Temperature Measurement with a Wheatstone Bridge
In this lab, we designed an Op amp circuit with a wheatstone bridge and a difference amplifier. Balancing the bridge was an integral part of this lab. If the bridge doesn't get balanced, we almost get to voltages where the op amp is saturated. We designed a bridge circuit.
2. Wheatstone bridge and difference amplifier design
Since the thermistor was 10.7kOhms at room temp, we put an extra 700 ohms in series with the top left resistor to balance the circuit. We chose resistors for the op amp circuit such that gain would be greater than 6, to amplify .4V difference to be amplified to 2.4V. We therefore chose 6.8k resistors for R2 and R4, and 10K resistors for R1 and R3 for an associated gain of 6.8.
1. Data:
We achieved our target goals, with an input difference of .43V amplified to a difference of 2.2V. We expected a gain of 2.9 Volts with the given resistance, which implies that either we failed to account for some resistance, or that our Op Amp was approaching saturation. Since our feed on the op amp was 5V, we assume the former, that some resistance was unaccounted for.
Exercise 2- DAC
This lab was pretty neat, since we were introduced to transforming a digital signal to an analog one. To do this, we use resistors that scale exponentially, and several input voltages. We did an example problem. The digital signals are amplified such that each increment in the analog output corresponds to a one or a zero on the digital voltage inputs. Notable: the "digital" voltage inputs must be a constant one or zero; if one input in half the expected input voltage, everything breaks.
We were also introduced to instrumentation amplifiers, which amplify the difference between two input signals. These guys can come in single IC packages, but aren't cheap, about $2/ IC.
gain for these are:
Av = 1+2R/R_g
Kevin was tired, class would start quite soon
His birthday arrived without a great ruckus
Until Thor clanked his coffee gear in among us.
I made coffee for Kevin (and the class) on his birthday. I might have put more than just coffee in. Happy 21st Kev.
Today's lecture was a simple linear continuation on the Op Amps discussing we've been having for awhile. We talked about cascaded Op Amps. Cascaded Op amps are simply a group of Op amps that stack gains multiplicatively (a devious word to spell). In contrast to that devious word, these Op amps are fairly easy.
A = A1*A2*A3
The cascade connection, it should be noted, can very easily saturate the Op Amp. Don't do that unintentionally. We did a bit of practice with this.
LAB- Part 1
Temperature Measurement with a Wheatstone Bridge
In this lab, we designed an Op amp circuit with a wheatstone bridge and a difference amplifier. Balancing the bridge was an integral part of this lab. If the bridge doesn't get balanced, we almost get to voltages where the op amp is saturated. We designed a bridge circuit.
2. Wheatstone bridge and difference amplifier design
Since the thermistor was 10.7kOhms at room temp, we put an extra 700 ohms in series with the top left resistor to balance the circuit. We chose resistors for the op amp circuit such that gain would be greater than 6, to amplify .4V difference to be amplified to 2.4V. We therefore chose 6.8k resistors for R2 and R4, and 10K resistors for R1 and R3 for an associated gain of 6.8.
1. Data:
We achieved our target goals, with an input difference of .43V amplified to a difference of 2.2V. We expected a gain of 2.9 Volts with the given resistance, which implies that either we failed to account for some resistance, or that our Op Amp was approaching saturation. Since our feed on the op amp was 5V, we assume the former, that some resistance was unaccounted for.
Exercise 2- DAC
This lab was pretty neat, since we were introduced to transforming a digital signal to an analog one. To do this, we use resistors that scale exponentially, and several input voltages. We did an example problem. The digital signals are amplified such that each increment in the analog output corresponds to a one or a zero on the digital voltage inputs. Notable: the "digital" voltage inputs must be a constant one or zero; if one input in half the expected input voltage, everything breaks.
We were also introduced to instrumentation amplifiers, which amplify the difference between two input signals. These guys can come in single IC packages, but aren't cheap, about $2/ IC.gain for these are:
Av = 1+2R/R_g
Thursday, April 6, 2017
Thus, It begins anew; no Operational Amplifiers for you
Woke up late this morning. Fortunately, an hour late for me is still 6:52, and I made it to class on time. Even had time to shower, make coffee, wash dishes, and run a wet swiffer my bathroom's (presumably fake) hardwood floors. Unfortunately I didn't have time for a walk. Or to shave. It was a good and hairy morning, nevertheless.
To school I travelled, and to class I went. Upon entering the room, Mason met my eyes. His beard bristled in indication of his anticipation for another day of excellent engineering. His eyes teemed with knowledge waiting to be shared. The knowledge of a new world unbeknownst to most non-engineers. This was the world of XKCD comics. He made a joke about sociologists. We did a simple inverting op amp example circuit. And Mason saw that it was science.
We did a one of these, calculated gains, noted voltage rails.
Alex made a diagram. We watched with admiration.
We did a one of these, and did nodal analysis. There was a significant moment where we realized that the voltage on both inputs of the Op amp is about zero.
Then we were instructed in the summing amplifier. The equation for this is simply the sum of those three Voltages over their respective resistances. So, as the middle equations notes, Vout is the sum of the voltages if R1=R2=R3=..., times the ratio of Rf to Rin.
Lab 1 of 2
Summing Op Amp
We select R1 = R2, and use the inverting equation from above. Values and measurements below:
We talked about another amplifier. It had 4 resistors of non-equal resistances, and was anything but simple. Difference amplifier. Complication equation. If R3=R1, R2=R4, the equation gets much better. If all are equal, then the output is simply the difference.
Lab 2: Difference Amplifier
Select R1=R3=10kOhm, R2=R4=21.5kOhm
Replace R3 with R2 in the below equation:
To school I travelled, and to class I went. Upon entering the room, Mason met my eyes. His beard bristled in indication of his anticipation for another day of excellent engineering. His eyes teemed with knowledge waiting to be shared. The knowledge of a new world unbeknownst to most non-engineers. This was the world of XKCD comics. He made a joke about sociologists. We did a simple inverting op amp example circuit. And Mason saw that it was science.
We did a one of these, calculated gains, noted voltage rails.
Alex made a diagram. We watched with admiration.
We did a one of these, and did nodal analysis. There was a significant moment where we realized that the voltage on both inputs of the Op amp is about zero.
Then we were instructed in the summing amplifier. The equation for this is simply the sum of those three Voltages over their respective resistances. So, as the middle equations notes, Vout is the sum of the voltages if R1=R2=R3=..., times the ratio of Rf to Rin.
Summing Op Amp
We select R1 = R2, and use the inverting equation from above. Values and measurements below:
We talked about another amplifier. It had 4 resistors of non-equal resistances, and was anything but simple. Difference amplifier. Complication equation. If R3=R1, R2=R4, the equation gets much better. If all are equal, then the output is simply the difference.
Lab 2: Difference Amplifier
Select R1=R3=10kOhm, R2=R4=21.5kOhm
Replace R3 with R2 in the below equation:
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