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!!