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Buying parts for circuits course
I’m going to need some parts to play with for the circuits course. While I probably could get the parts I need at work from the Baskin Engineering Lab Support (BELS) staff, it would probably involve a...
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Op-amp lab
Since the thermistor lab seems to have worked fairly well (see More musings on circuits course: temperature lab, Buying parts for circuits course, Temperature lab, part2, and Temperature lab, part 3:...
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Instrumentation amp lab
I did some playing around with a simple op-amp amplifier to try to get an EKG signal, based on ideas like those in DIY ECG Machine On The Cheap, but I was unsuccessful in seeing anything other than...
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Instrumentation amp, try 2
I did some more playing around with the 2-op-amp instrumentation amplifier and finally got it to sort-of work. The gain should be , that is 30.8kΩ/6.8kΩ + 48kΩ/330Ω or 150. I put in C1 to block the DC...
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Capacitive sensing with op amps
I’m not very happy with the lab exercise in Capacitive sensing. The basic design questions are good: What capacitance do we add by touching something? What frequency should the oscillator run at...
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Capacitive sensing with op amps, continued
What more can I do (or, more importantly, have the students do with the Capacitive sensing with op amps? The circuit that I gave in that post has several parameters. Perhaps the students should try...
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EMG and EKG works
I decided to try the instrumentation amplifier again, doing an electromyograph, rather than an electrocardiogram. The principle is the same, but you get the signal from a muscle other than the heart....
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Two-stage EKG
In EMG and EKG works, I described an EMG and EKG that worked, but I was not completely happy with. The output was too small and too noisy to feed into an Arduino for data logging. For this post, I...
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EKG recording working
My son and I spent some time today debugging his data logger. I also convinced him to add some documentation, though not nearly as much as I think is needed. This version is just a text command...
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More thoughts on EKG
Before doing the EKG lab, we should definitely discuss safety concerns, including things like the following chart (information from http://electronicstechnician.tpub.com/14086/css/14086_34.htm): Human...
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Random thoughts on circuits labs
DNA melting I spent some time yesterday thinking about whether we could do optical detection of DNA (particularly some variant of the DNA melting lab from MIT—see also the Fall 2008 class handouts). I...
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Order and topics for labs
I had a good discussion with Steve P. this afternoon about the order and purpose of the labs I’ve designed so far. He’ll be putting together a list of EE topics we have to cover to coordinate with the...
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Pressure sensing lab possibilities
I’ve been thinking about a lab in the middle of the circuits course that uses linear circuit modeling techniques to model a non-electrical system. This is a common engineering technique, particularly...
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Supplemental sheet for lab, draft 1
In my previous post, I said that I would post drafts of my supplemental sheets describing the course here on my blog, to get feedback before submitting them. Since I’ve been thinking more about the...
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Supplemental sheet for lecture, draft 1
I did a draft supplemental sheet for the lab course, which is nearly complete, though there are 2 labs that need some more work (the phototransistor lab and characterizing fluidics). I also need to...
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Supplemental sheets, draft 2
This post updates and replaces the Supplemental sheet for lecture, draft 1 and Supplemental sheet for lab, draft 1 Lecture Course Undergraduate Supplemental Sheet Information to accompany Request for...
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Capacitive sensing with Schmitt trigger
Capacitive sensing with op amps and Capacitive sensing with op amps, continued used a rather complicated circuit to make a Schmitt-trigger oscillator out of op amps: Modified circuit for longer period....
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Disappointing power-amp lab
Today was a rather disappointing day for me. I spent most of the day working on developing a decent power-amp lab, and I’m not happy with what I’ve got so far. You may remember from my earlier post...
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Parts packed, pressure sensors assembled, more thoughts on power amp
The DigiKey order arrived today, so I spent some time repacking all the parts into DIP tubes and little plastic bags. I also assembled and soldered all 12 of the breakout boards for the MPX2053DP...
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Class D instead of class AB
I tried doing a very simple class D amplifier with the FETs today. The idea was very simple: I took the one-op-amp amplifier I had built before, and added a comparator comparing that value with a...
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