I typically buy a new personal laptop computer every 5-6 years. I was a diehard Windows person until Windows Vista came along when I crossed over to the Mac world. I've been a Mac person ever since.
Because I keep my computers for a long time, when I buy I always load up on hardware. I typically go for the fastest processor, most memory and the largest storage drive. Today I decided to price up a new loaded MackBook M3 Max and was blown away by the price - $7200!
Pondering, I decided to skip the $19 Apple Polishing Cloth. I can always pick one up later.
Granted, maxed out the configuration is for high end niche users and not users like me. My 14 inch M1 Pro is only two years old with 16 GB RAM and a 1 TB SSD so..... I'll just hang on to that for now.
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 555timer is still one of the most popular components used in timing-related applications.
Thanks for visiting. I'm Gordon, past National Science Foundation Funded Centers of Excellence Director and Co-Director at Springfield Technical Community College and University of Central Florida, past Visiting Engineering Professor at the University of Hartford, currently an Adjunct Computer Science Professor at Pace University and an Adjunct Engineering Professor at Holyoke Community College in Massachusetts. I’ve authored four engineering and engineering technology textbooks and have over 40 years of engineering, technology, communications and IT teaching experience. In addition to my teaching and work with NSF Centers of Excellence, I've served as the Verizon Next Step New England telecommunications curriculum leader and on several business and technology boards around the United States including the Microsoft Community College Advisory Council, the Massachusetts Networking and Communications Council and the National Skill Standards Board.
I am one of the co founders of the Hi-Tec Conference that annually brings 500-600 academic, business and industry representatives to explore the convergence of scientific disciplines, engineering and technologies.
In 2001, I was selected as one of the top 15 STEM faculty in the United States by Microsoft and the American Association of Community Colleges and in 2004 was selected as the Massachusetts Network and Communications Council Workforce Leader of the year.
I am also certified by the International Distance Education Certification Center as a Certified Distance Education Instructor.