555 Timer: Astable Mode

The 555 timer IC is a popular integrated circuit (IC)  used in various electronic projects and can be configured to perform a wide range of tasks. It was first introduced by Signetics (now part of ON Semiconductor) in 1972 and has since become one of the most widely used ICs in the electronics industry due to its simplicity and versatility. The 555 timer IC is available in different variants, including the NE555, LM555, and others, with minor variations between them.

The 555 timer operates over a wide range of power supply voltages, typically from 4.5 volts to 15 volts and is typically used in one of three operating modes:

• Astable Mode Operation: In this mode, the 555 timer acts as an oscillator, generating a square wave output signal. This mode is commonly used in applications like LED flashers, pulse generators, and tone generators.

• Monostable Mode Operation: In this mode, the 555 timer functions as a "one-shot" pulse generator. It produces a single pulse of a specified duration in response to a trigger input. Applications include timers and delay circuits.

• Bistable Mode Operation: This mode is used to create a flip-flop circuit, which has two stable states and is often used in simple digital logic applications.

Depending on how a 555 timer is to be used, the appropriate configuration and values for the timing components (R1, R2, and C) must be selected to achieve the desired output characteristics or time delays. Here's some details:

• Timing Component Operation: The 555 timer's timing is determined by two resistors (R1 and R2) and a capacitor (C). By choosing appropriate values for these components, you can set the desired time intervals for the timer's operation.

• Internal Comparator Operation: The 555 timer includes an internal comparator that compares the voltage across the timing capacitor with two-thirds of the supply voltage and controls the output accordingly.

• Output Stage Operation: The 555 timer has an output pin (usually labeled as "OUT") that produces either a high or low signal based on the timing mode and the voltage across the timing components.

• Trigger and Reset Input Operation: The IC has a "TRIG" (trigger) input and a "RESET" input. The trigger input is used to initiate certain modes of operation, while the reset input is used to reset the timer and interrupt its operation.

• Threshold Input Operation: The "THRS" (threshold) input is used in some applications to override the internal voltage divider.

Here's a short PSpice video I made demonstrating how the 555 Timer can be used in Astable Mode.

The 555 timer is still one of the most popular components used in timing-related applications. 

MATLAB Tip Calculator on Your Phone

In this video I show how to take your MATLAB code and run it on your iPhone. 

Here's a list of instructions you can use while watching the video.

In MATLAB on Your Computer

• Create a MATLAB script or function.

• Document your code by adding explanatory comments at the beginning of the file and within each section.

• Publish the code. On the Publish tab, click Publish.
• By default, MATLAB creates a subfolder named html, which contains an HTML file and files for each graphic that your code creates. The HTML file includes the code, formatted comments, and output. Alternatively, you can publish to other formats, such as PDF files or Microsoft PowerPoint® presentations. For more information on publishing to other formats, see Specify Output File.
• In MATLAB Online™, to allow MATLAB to open output windows automatically when publishing, enable pop-up windows in your Web browser.

• After publishing the code, you must share the folder containing the published files. For more information, see Share Folders in MATLAB.

• To share a folder from MATLAB®, MATLAB Drive Connector must be running and the folder you choose to share must be in your MATLAB Drive. If you are working in MATLAB Online, you do not need MATLAB Drive Connector to share folders since sharing is always enabled.
• See: https://www.mathworks.com/products/matlab-drive.html

• To save to the MATLAB Drive, in MATLAB select Publish -> Save -> Save As -> navigate to MATLAB-Drive and save tipcalculator.m there.

On Your Phone

• Install the MATLAB app on your phone, login to your account and access the script saved in to cloud. You must have internet access to access.

• Impress your family and friends with your tip knowledge, skills and abilities!

And if you want to also impress them a little more, here's how to mirror your iPhone screen on a Mac.

1. Connect your iPhone to your Mac with a USB cable.
2. Open the QuickTime Player on your Mac.
3. Click “File”, and choose “New Movie Recording”.
4. Click the Options pop-up menu, then Choose Your Connected iPhone. ...
5. The iPhone screen will now instantly display on the Mac.

MATLAB Tip Calculator Fix-Up

This summer I'm building a series of MathWorks MATLAB (short for Matrix Laboratory) videos for an introductory online course I'm putting together at Holyoke Community College.

 

In this video I fix-up a previously saved tip calculator script in MATLAB. In the next video I'll show you how to transfer the script to your cell phone so you can use it when you eat out!

The course will start from ground zero assuming the student has no experience with MATLAB and work up to some interesting and powerful analysis techniques. Over the summer I’ll be posting additional MATLAB videos as teasers for the complete course.

 

Want to learn more? Come take a course with me at Holyoke Community College. If you are anywhere in the world and interested in taking an online course, drop an email to gsnyder@hcc.edu Our courses will transfer to most university engineering programs in the United States. 

Write, Save and Run A Tip Calculator Using MATLAB Scripting

This summer I'm building a series of MathWorks MATLAB (short for Matrix Laboratory) videos for an introductory online course I'm putting together at Holyoke Community College.

In this video I demonstrate how to write, save and run a tip calculator script in MATLAB. In the next video I'll show you how to transfer the script to your cell phone so you can use it when you eat out!

The course will start from ground zero assuming the student has no experience with MATLAB and work up to some interesting and powerful analysis techniques. Over the summer I’ll be posting additional MATLAB videos as teasers for the complete course.

 

Want to learn more? Come take a course with me at Holyoke Community College. If you are anywhere in the world and interested in taking an online course, drop an email to gsnyder@hcc.edu Our courses will transfer to most university engineering programs in the United States. 

MATLAB Basic Functions Video - Restaurant Tip Calculator

This summer I'm creating a series of MathWorks MATLAB (short for Matrix Laboratory) videos for an introductory online course I'm putting together at Holyoke Community College. Here's a new 4 min 52 sec how-to video using a simple restaurant tip calculation as an example.  Full course videos and content will get into the MATLAB app with lots of hands-on practical and fun examples.

The course will start from ground zero assuming the student has no experience with MATLAB and work up to some interesting and powerful analysis techniques. Over the summer I’ll be posting additional MATLAB videos as teasers for the complete course.

 

Want to learn more? Come take a course with me at Holyoke Community College. If you are anywhere in the world and interested in taking an online course rop an email to gsnyder@hcc.edu Our courses will transfer to most university engineering programs in the United States. 

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!!

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!!

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!!

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!!