Sunday, August 1, 2021

PSpice Lab Series Video 5 - Batteries In Parallel

Maybe you've got an RV or a boat with four or more house batteries used to power an air conditioner, oven, electric grill, etc. Maybe you've got a cabin off the grid and are harvesting solar energy to charge a battery bank. Ever wonder what those batteries are doing and how they are hooked up?

In this video I use PSpice to demonstrate how multiple batteries are connected in parallel in a power inverter, solar hybrid inverter or UPS (Uninterruptible Power Supply) to increase capacity and run your ac, oven, etc longer on a full charge.



For more PSpice laboratory simulations, visit my YouTube PSpice Playlist.

Want to learn more? I’ll be teaching a Systems 1 course online in the fall and a Systems 2 course in the spring at Holyoke Community College. If you are anywhere in the world and interested in taking an online course with me drop an email to gsnyder@hcc.edu Both courses will transfer to most university electrical engineering programs in the United States. 

Hope to see you there!!

Thursday, July 22, 2021

Internet Access In Support Of The Cuban People


I was in Cuba four years ago. The government had tight control of just about everyone and everything including Internet access back then so I’m not at all surprised they’ve been able to shut communications down amid the protests. I’ve been reading a lot about alternative access for Cubans lately. Satellite has been getting a lot of questions but the network and mobile devices are still a ways out. 

Today, balloons probably offer the best solution. Google actually has them ready to go with project Loon. Loon has been proven in collaboration with Telecom Kenya and used in Puerto Rico in partnership with AT&T and T-Mobile after Hurricane Maria. Each Loon balloon is made of polyethylene and has solar panels for electricity. They float between 60,000 and 75,000 feet which is above commercial airline height and provides 4G cell service to an area about the size of a tennis court. The problem – Loon requires network integration with a telco to provide service along with some equipment on the ground. Loon also requires permission from local regulators — something that the Cuban government surely would not grant.

Marcell Felipe, founder of the Inspire America Foundation, an organization dedicated to promoting democracy in Cuba and the Americas has been discussing a slightly different balloon idea without a lot of detail. Felipe claims he has been talking for a couple years with a contractor (not named, but could it be….??) that could deploy balloons that provide mobile phone connectivity without the participation of a ground provider. In comments to The Associated Press, Felipe has claimed it wouldn’t be feasible for the Cuban government to block these balloon-delivered signals “in any significant manner.″


Pic: Telecommunications Building, Revolution Square Havana. G Snyder 2017

Sunday, June 13, 2021

PSpice Lab Series Video 4: Voltage and Current Linearity In A Simple Resistive Circuit

In this video I use PSpice to take some measurements and Excel to record the measurements and make a simple graph showing the linear relationship between voltage and current in a simple DC resistive circuit.

Want to learn more? I’ll be teaching a Systems 1 course online in the fall and a Systems 2 course in the spring at Holyoke Community College. If you are anywhere in the world and interested in taking an online course with me drop an email to gsnyder@hcc.edu Both courses will transfer to most university electrical engineering programs in the United States. Hope to see you there!!

Thursday, June 10, 2021

Pspice Lab Series Video 3: Moving The Reference Ground Around

Zero volts reference, also known as ground is always a confusing topic. What if ground is placed at different locations in a circuit? In this 11 minute and 42 second video I use PSpice to show what happens when you move a ground around in a series circuit.

Want to learn more? I’ll be teaching a Systems 1 course online in the fall and a Systems 2 course in the spring at Holyoke Community College. If you are anywhere in the world and interested in taking an online course with me drop an email to gsnyder@hcc.edu Both courses will transfer to most university electrical engineering programs in the United States. Hope to see you there!!

Wednesday, June 2, 2021

Pspice Lab Series Video 2: Simple Series Resistive Circuits

 Here's a second PSPice video covering analysis of a simple series circuit with two dc voltage sources and four resistors.

Want to learn more? I’ll be teaching a Systems 1 course online in the fall and a Systems 2 course in the spring at Holyoke Community College. If you are anywhere in the world and interested in taking an online course with me drop an email to gsnyder@hcc.edu Both courses will transfer to most university electrical engineering programs in the United States. Hope to see you there!!

Sunday, May 30, 2021

Uncle Stash’s Silver Star

“Every man has two deaths, when he is buried in the ground and the last time someone says his name.”
― Ernest Hemingway


Stash is short for Stashu and Stashu means Stanley in Polish. He was married to my grandmother’s sister Ruthie who passed away in February 2020. Stash passed away in 1963 when I was six. I don't remember much about him but there were always stories about Stash in World War II. Rumors he was a member of a special forces group that captured a high level Nazi general. 


Stash worked in a factory in Springfield, MA before and then after the war. From what my parents have told me he was the kind of person that went to work, came home and went back to work again the next day. Never talked about the war but does have a Silver Star on his gravestone. 


After Aunt Ruthie passed away I did a little poking around on the web and came across Stash’s Silver Star Citation:

The President of the United States of America, authorized by Act of Congress July 9, 1918, takes pleasure in presenting the Silver Star to Sergeant Stanley J. Schab (ASN: 313466007), United States Army, for gallantry in action while engaged in military operations involving conflict with an armed hostile force while serving with Company M, 143d Infantry Regiment, 36th Infantry Division, in action against the enemy on 3 December 1944 in France. Sergeant Schab and his men were manning a machine gun in a house on the edge of a town when a large group of the enemy infiltrated around the building and cut their communication lines. Although hostile fire was coming through every window of the house, Sergeant Schab moved from man to man, firing his sub-machine gun from each position to encourage them. When a burst of automatic weapons fire knocked his gun from his hands, he picked the weapon up and continued to fire. One group of the enemy succeeded in reaching the yard, but Sergeant Schab killed two Germans and wounded another within five feet of the rear door. His vigorous and determined defense forced the enemy to withdraw. Later in the day, as he moved his outpost forward, he surprised and captured five Germans who were attempting to return to their own lines. When two other Germans tried to rescue their comrades, he killed one and wounded the second. His gallant actions and dedicated devotion to duty, without regard for his own life, were in keeping with the highest traditions of military service and reflect great credit upon himself, his unit, and the United States Army.

December 3, 1944.... today it's just another day a long time ago - an obscure link on the web and a gravestone marker in a small cemetery in Western Massachusetts. 


So many veterans like Stash - a regular guy that went off, did some heroic stuff, and was fortunate enough to come back home to his regular life.... so we can have our regular lives. Many did not get to come back and many came back very different people. The world sure would be a very different place without our current service members and veterans stepping up. Hemingway finishes: 


"Stories, too die when the last person who knows the story dies. So the trick is not only to know the story, but to make people remember the story, so it will live on.”

We can't forget.

Sunday, May 23, 2021

PSpice Lab Series Video 1

Over the summer I’ll be working on a series of OrCAD PSpice videos. PSpice is one of the most common analog and mixed signal circuit simulator and verification tools used by electrical engineers to rapidly move through the design cycle, from circuit exploration to design development and verification. It is also a lot of fun to play around with!

I’m developing a series of 25-30 online experiments that we’ll be using in my EGR223 - System Analysis (Circuit Analysis 1) and EGR 224 - System Analysis (Circuit Analysis 2) courses at Holyoke Community College. Here’s the first video in the series.




OrCAD has an excellent academic program that provides students and educators with a complete suite of design and analysis tools to learn, teach, and create electronic hardware. If you are a student or educator you can download the software here for free and follow along with my labs. If you are not a student or educator (or perhaps considering) you can download and install a trial version of the software here.


I’ll be teaching the Systems 1 course online in the fall and the Systems 2 course at Holyoke Community College in the spring so if you are anywhere in the world and interested in taking a course with me drop an email to gsnyder@hcc.edu Both courses will transfer to most university electrical engineering programs in the United States. Hope to see you there!!

Monday, May 3, 2021

Can Success Be Taught?

Success .... Is it luck? Timing? Purely based on abilities and talents we are born with? Can it be learned? Can we teach it to our children? Why are some more successful than others? Can it be taught and learned  Hmmmmm….

Bill Murphy wrote something back in 2016 over at inc.com that I’ve had bookmarked titled Want to Raise Successful Kids? Science Says Praise Them Like This (but Most Parents Do the Opposite) with the tag line Stop praising kids for their innate or God-given abilities, and instead focus on their effort.

In the piece, Bill describes the work of Dr Carol Dweck, a Stanford University Psychology professor that did a couple of studies involving school age children and learning. In both studies Dr Dweck examines the difference between a growth mindset (belief that achievement is variable and intelligence and problem-solving abilities can be developed over time ) and a fixed mindset (belief that intelligence is almost entirely innate and you are born with it) and how that can impact success, arguing growth mindsets can have a much larger impact on success compared to fixed mindsets.

What does this mean? Let’s use a sports analogy. A person with a fixed mindset might say, "Tom Brady was born with super athletic ability" while a person with a growth mindset might say “Tom Brady has worked incredibly hard to get to where he is today.”  

Bill Murphy breaks things down pretty nicely from a parent perspective. I’ll tweak his writing, approaching as an educator with a focus on students.
  • Praising students merely for their innate abilities, such as their intelligence, actually makes it less likely that they'll grow up to enjoy learning and to excel.
  • Praising students instead for the strategies and processes they develop to solve problems--even when they don't fully succeed--makes them more likely to try harder and ultimately achieve.
Can success be taught? No doubt - yes. Take a look at Dr Dweck’s research and check out some of Bill Murphy’s writing for more.

Thursday, April 1, 2021

Nice Overview Video - Low Earth Orbit (LEO) Satellite Internet

The Wall Street Journal  recently went up to a remote area of Washington state to talk to some beta testers and take a look at SpaceX's new Starlink satellite internet service. 


This short 9 minute and 30 second video gives a nice overview of how low earth orbit satellite networks like Starlink are one piece of the puzzle in solving the global broadband divide problem.



It’s good and watching with students should generate some very interesting classroom discussion.

Sunday, February 28, 2021

Nonverbal Overload In An Online Engineering Classroom


Last week, Stanford researchers published a new study: Nonverbal Overload: A Theoretical Argument for the Causes of Zoom Fatigue. The study is a first shot at pointing out Zoom, WebEx, etc design flaws to isolate research areas for social scientists and to suggest design improvements for technologists. Researchers found four quite different causes for fatigue and recommend solutions for each:


Close-up eye contact is exhausting. Solution: Minimize the face sizes of attendees into grid view, and sit back a bit to allow yourself more personal space. 

Watching yourself is exhausting. Solution: Confirm that your lighting and setup look good, and then adjust the settings to hide your view of yourself.

Sitting immobile is exhausting.  Solution: Create a wider visual field for your camera. 

Video chatting is cognitively exhausting. Solution: When it’s feasible, turn off your camera for breaks—and turn your body away from the screen.


It's all exhausting! I’ve done some of my own experimenting and agree with the Stanford findings when it comes to the online classroom. Here’s how I’ve been working on some course content delivery improvements in one of my online classes.

Pre-Recorded Lectures
I’ve been pre-recording lectures  for about a year now and posting them. In one of my classes I recently started watching them with students during class sessions – I share my screen and audio, playing the videos.  Electrical engineering courses are 95% applied math and lectures typically involve a short introduction to a topic and then working sample problems. I am not a fan and do not use PowerPoint. I record lectures using an iPad and Apple Pencil. 

Class Sessions
Students are required to take notes as they would in a traditional in-person lecture with me writing on a board in front of the class. They ask questions, verbally or in the chat box. By watching my own lectures with the students, I’ve found myself much more aware of non-verbal cues. I’m able to watch the chat box, catch any mistakes I’ve made, pause a video for discussion, etc. I’m no longer sitting with my head down writing on an iPad, cranking out math problems while what seems like talking to myself. I’m much more focused on the students and the way I’m explaining the material. When they ask me to pause a video, I have a pretty good idea they are following the lecture and taking good notes!

Assessment
After each class is over, students are assigned between 1 and 3 quiz/homework problems that are due the next day at noon. I also post the videos for students to access.

Breaks
I do try to squeeze a 5 min break in when I can even though I’ve not been very good at that. I also try and keep videos to around 25 minutes so if we miss one of the 5 minute breaks there is a natural break between each video. 

Cameras
Students typically do not turn their cameras on and I’m ok with that in my classes. Some faculty will disagree.

Future Plans
We're charting new ground so every day is a work in progress - so far student feedback has been very positive with plans to further refine (have some interesting ideas for exams) and expand methods to other classes I teach.

Friday, February 19, 2021

Divergence Theorem - Electrical Engineering Class Snap Video

I've become a big fan of what I call snap videos while teaching remotely. Here's a simple example I used recently to explain a concept that is relatively simple to describe in a traditional face-to-face class but maybe not so simple for students to understand while learning online.

Every undergraduate electrical engineering student needs to take an electromagnetics course. This course is a little different than most of the other required courses that use wires, resistors, capacitors, transistors etc, all physically (and in most cases two-dimensionally) connected together. 

In much of this course there are no wires and everything in three-dimensions - I sometimes refer to it as the "magic" course. The math is advanced calculus based but I've found if a student has made it far enough to be taking this course they've got the math down and can handle it. Conceptually is where they often stumble - trying to get a picture in their head of what is going on in three dimensions. 

The Divergence Theorem is a good example. In electromagnetics it is used to identify by location like sources and sinks. It is also used to explain the rate of change of a function with respect to position. Important stuff for things like cell and wifi signals along with a bunch of other "magic-based" technologies.

The math includes a couple methods called volume integration and surface integration. The volume integration is pretty easy - a student can bang through the math and get an answer without really having a good picture in their head of what is going on. Surface integration is a speed bump, wrong way turn, etc for many. I know it was for me when I was first learning this stuff. It really cannot be done without an accurate mental picture of what is going on. The classic way to introduce this topic uses a cube drawn in three dimensions on the board. Here's one of my (not so good) drawings in three dimensions (x, y and z axis) as an example. 
The cube (yeah, that's a cube!) has all six sides labeled and to solve the problem students need to do surface integration math on each of the six sides individually and then combine the six answers for a final answer. Which side is which is where the confusion lies - which on is side 1?? Looking at my drawing above - I can't figure it out.... My diagram is pretty much useless!!

When teaching in the classroom I hold up a box and describe and label the different sides with the students. Can't do that online so..... how about a video. Here's a quick one I put together a couple days ago, describing and hopefully explaining the confusing parts. 


I'm using an Apple iPad with Apple Pencil along with the GoodNotes app. I find it useful to "think out loud" when I do these. It is also the way I teach - thinking through a problem step by step with the students. I do not do any editing so this 6 minute video took maybe 10 minutes total to record and upload to YouTube.