CS 352 Lecture 4 – Relays
Dear students,
We looked last time at the elements of electronic circuits: switches, voltage sources, resistance, and some sort of output device—in our case, an LED. In putting these parts together in various ways, you can build a piece of technology with a very fixed purpose. If you want the hardware to do something else, you must recombine the components. This is very much how the first computers operated. Instead of writing code, early programmers rerouted wires. Thankfully, modern computers do not need their hardware reconfigured in order to switch between applications.
Today we look at a component that will ultimately allow computers to reconfigure themselves, on the fly! We introduce this component by stepping back into the world of Samuel Morse. He invented the telegraph, which had its own API: Morse code. The intent of the telegraph was to send Morse code signals across far distances. How did he do it? We will see that far was achieved through the use of a relay. With computers, we’re not as considered about sending signals far away as we are letting one circuit influence another indirectly. A relay represents to us an electrically-controlled switch. Instead of a human being or a physical phenomenon bridging a pathway in our circuits, we can have another circuit do it!
We will look at how relays operate and how we can combine them in interesting ways.
I expect to get a grade report sent out tomorrow via email. I don’t use D2L. It won’t report much at this point in the semester.
See you next class!
