25.151 Assistive Technology & Electronics
Lab 4: 555 Timers, Data Sheets, and Using Integrated Circuits
Objectives:
- Experiment with interesting applications of 555 Timer circuits
- Familiarize yourself with the useful information available in component data sheets, including power ratings, functionality, and applications
- Understand the “black box” nature of IC’s—if you can read a data sheet, it opens up a world of applications to an electronics novice
Introduction:
The “555 Timer” is a well-known chip that has many practical uses for both beginners and experts. For example, the last circuit in Lab 2 used the 555 timer in “astable mode” to turn an LED on and off in a very predictable (periodic) pattern. Perhaps a blinking LED is not very useful, but with a bit of thought, you could think of many ways to use this controllable output for much more useful purposes.
More important is the fact that all of these 555 applications are spelled out in the manufacturer’s data sheet for the chip (and if you Google “555 timer” you will find hundreds of other resources, circuits, etc. for the 555 timer). Chips (integrated circuits, of ICs) have been developed to accomplish many useful tasks, including tasks you may find useful for your ATDF project.
All you need to do to find and use these chips is to:
- know how to “Google”
- be able to selectively read the data sheets to glean the important information (power requirements, application instructions, etc.)
- be willing to experiment/breadboard
- know when to ask for a little help from someone with more experience
Due Date/Scheduled Lab time:
- Hand in on or before Thursday, March 20.
- We scheduled one day in lab for you to experiment. You'll have self-managed time over the next week to complete.
- Part I is research outside of class (but feel free to ask for clarification in class) - for the most part you should work on this as an individual assignment and come up with unique answers (at least for certain questions), but feel free to consult with each other to "keep things moving"
- Part II is meant to be started in the lab, but much can be done at home. Work on this with a partner(and identify your partner in your lab writeup)
