Showing posts with label Electrical. Show all posts
Showing posts with label Electrical. Show all posts

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 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!!

Thursday, January 10, 2013

Tektronix Oscilloscope Tutorials

I came into Electrical Engineering a different way than most - starting as a graduate student with an undergraduate degree in Microbiology. These two disciplines are slightly different - Microbiologists use microscopes and EE's use oscilloscopes :) I knew I had some catching up to do and remember one of my major goals for the summer before I started grad school was to learn how to use an oscilloscope. Fortunately I came across a free tutorial booklet from Tektronix on understanding and using an oscilloscope which made it pretty easy.


Well, even though that was over 30 years ago now, the Tektronix free tutorial materials still exist and they are even better than before. If you are starting from scratch or just want to brush up these are highly recommended. Here's a link to the tutorial page. Good stuff!

Saturday, August 11, 2012

Curiosity on Mars Bringing Back Memories

The Mars landing of Curiosity has brought back some memories when it comes to sensors and systems in space.....

It was 1980. I was a year out of college with an undergrad degree in microbiology and working in a hospital lab trying to figure out what I wanted to do for the rest of my life. At one time I had thought I wanted to go to medical school but the more time I spent in a hospital working in a clinical setting the more I realized I was not cut out for that kind of work. I loved the biology but I was struggling with the procedures - the work was 100% protocol - the same procedures over and over again with zero room for mistakes. So many of the people I worked with were so good at it - they thrived on it.  Me - I had always loved tinkering, taking things apart and trying to put them back together. Trying new things that did not always work was what I liked. Trying this instead of that. What if I did this? What would happen?

But.... when you are dealing with people's lives you can't do that kind of stuff. I have so much respect and envy for people who do this kind of work but I knew it ultimately was not for me. I loved the science but knew I had to change directions with respect to my career. Fortunately, something came along (as it often does in life) that helped me with my dilema.

In the lab one day we started testing a machine called the VITEK for McDonnell Douglas and NASA. VITEK was a fully automated microbial identification and susceptibility system that had been developed in the 1960's for use in space. The system is based on microbial growth in thin plastic identification cards that have small wells with sugars, enzymes, etc. After the cards have been inoculated with sample they are incubated at 37 degrees C and photometrically scanned every hour for either color change or turbidity. Different bacteria ferment different sugars, produce different byproducts, grow or don't grow based on nutrients or conditions, etc. Basically how they grow or do not grow is how they are identified.

McDonnell Douglas was looking to move the product from outer space into the hospital lab and we had engineers coming in and out of the lab weekly tweaking the system. We were running tests in parallel - we'd run a sample using traditional microbiological ID methods and run the same sample through the VITEK, comparing identification results. There was about a three week period when the engineers were in lots - the system was not working properly - something was screwed up in the incubation cycle and they were having a hard time figuring it out.

One of the engineers I had got to know came in with a large stack of green-bar  paper with thousands of lines of code one day. I had never seen actual code before - it was so logical and simple and organized. Really cool! I was able to look at it and quickly pick out where the error was - the incubation line was not properly placed in the incubation cycle loop. I showed the engineer what code lines needed to be swapped around and remember him scratching his head and shrugging his shoulders. Still, he made the mod and....... it worked! It was so trivial but it worked!! The engineers were looking too deeply into the code - this was sort of like a TV not working because it was not plugged in type of thing. That simple. I remember the guy telling me I should have been an engineer. I also remember him telling me the first time someone writes a program it never works and you always had to go back and troubleshoot it. I was intrigued - engineering - could it be for a tinkerer like me who likes to learn from my mistakes?

Well - long story short - my sister and two brothers had degrees in electrical engineering. They had been bugging me for a while to check out engineering. They talked me into going to see Dr Jim Masi (the same Jim Masi who was our first Director at www.ictcenter.org) at Western New England University and we were able to work out an agreement where I could pick up the undergrad courses I was missing and then move into an MS Electrical Engineering program. It took a while and most of the time was incredibly hard but I was able to complete the degree.

As an engineer I could now tinker and try new (sometimes off the wall) things and make mistakes and learn from those mistakes. And that microbiology background has never gone to waste - I know it has helped me think and approach problems a little differently than traditionally trained engineers. All good!