# Play-Hookey Website

#### While you're out of the classroom, there's no reason why you can't learn a little something and enjoy yourself while you're doing it. That's the basic purpose of this site.

Note:

Some of the pages on this site include frames and/or JavaScript applications. These pages are written to be as universal as possible, and will work with multiple types of browsers. Netscape has been discontinued and is no longer supported, although existing copies are still in use and will work fine. As a replacement, I recommend Mozilla Firefox. For those thrill-seeking individuals who prefer the security risks of Internet Explorer, IE4 and later will also handle the interactions currently in use. This site will never attempt to exploit the security holes offered by IE, but we do feel you should be aware of the hazard.

Other browsers, such as Opera, generally emulate one or the other, and should not present any problems.

The Logical Story.

Digital logic is at the core of all digital computers, and yet it is entirely based on three fundamental operations, designated AND, OR, and NOT. See how it's possible in these pages.

These pages now include coverage of the major logic families as well as some practical experiments that you can perform with real components to see for yourself how they work.

Note: Some interactions require Javascript 1.1 or later. Incompatible browsers will be limited to a static presentation.

Operational Amplifiers and Analog Computers.

Analog computers are not completely gone from the scene, in spite of the tremendous advances made in the digital field. And operational amplifiers (op amps) are used in many more applications than analog computers. Here is an overview of many applications for op amps, in and out of analog computers.

These pages now include some practical experiments that you can perform with real components to see for yourself how they work.

Electronic Theory: Direct Current.

Now that we have begun looking at both digital and analog circuitry, it is only appropriate to start looking at the components that make up these circuits, and to explore their properties. We begin this process here, with the fundamental properties of electronic components and the basic rules by which they operate in electronic circuits.

Electronic Theory: Alternating Current.

Even the most basic electrical components can behave differently for changing voltages than they do for steady voltages. Here we look as the AC properties of the basic components, and the resulting variations in circuit behavior.

Oscillators.

We've talked about alternating voltages and currents, and the AC properties of various electronic components. But how do we create those AC signals to apply to these components? Here is the bare beginnings of circuits designed to generate such signals over a wide range of frequencies.

Take a look at optics.

Light is a very interesting topic. Is it a wave? A particle? Why is the sky blue? How does a laser work? And what's this about "light pipes" that let light travel around corners and into impossible places? Some of the development work on this site is aimed at exploring these and other questions about light.

What's inside these semiconductors?

I've been getting queries about the internal structure and behavior of semicondutor devices. In response, here's a discussion of what semiconductors are, how they behave, and how various semiconductor devices are constructed.

Another set of pages, currently under development, will show the behavior of typical semiconductor devices in actual, working circuits.

Looking inside the computer.

Did you ever wonder what goes on inside that (mostly) featureless box that you're now using to view this page? How is it that gazillions of invisibly small things called "electrons" can figure out where to go and what to do to paint words and pictures on your computer monitor or TV screen? It obviously works since you are seeing the result, but how? And probably the most important question in most people's minds: "Can I do it, too?"

Well, the answer is, "Yes, you can, and it's not even all that hard." It is my intention to help you learn for yourself what is going on behind the scenes and how you can use it for your own purposes. I am in the process of building a set of sample lesson pages on computers and the people who work with them in various capacities; you can see them in progress by going to this link.

Testing HTML markup.

Have you considered writing your own HTML pages, but were unsure of how to get started? Here's a chance to write and test HTML markup, style sheet specifications, and even Javascript if you like, and to see the results without having to shift back and forth between different programs.

This interactive page uses both frames and Javascript.

This Website is intended for those intrepid individuals who, for whatever reason, find themselves looking for a less than formal approach to useful education in a number of technical fields. Unlike the University-based courses which I have found on the Internet, the "lessons" provided here will be available to anyone at any time, and at no cost. They also will involve no formal college credit.

To avoid getting caught by changes in this site, and to be sure you know about changes as they occur, please be sure to set a bookmark only to this home page -- I can promise that it will always be here as long as this site exists. Other pages may be moved or renamed for logistical reasons, but you will always be able to get there from here.

To recap, the following topics are currently available:

All material on this site will be designed and enhanced for Netscape Navigator version 3.0 or higher, and compatible browsers. They may at any time use both frames and JavaScript to provide an interactive means of learning on your own. If your browser does not support frames and JavaScript as well as forms, you may not be able to make full use of these lessons. We're not trying to exclude anybody, but as long as the "browser wars" go on (probably forever), we can't be all things to all people. We'll do our best.

Meanwhile, tests have shown that IE4 and higher can also handle the current interactions in the digital logic section.

This site is running on an Intel Core2 quad-core processor, running FreeBSD 8.3 and Apache 2 with mod-perl and HTML::Mason.

This site owned and operated as a hobby and for general interest by Ken Bigelow.

In response to numerous requests from around the world to use my site as an adjunct to one or another course of study, I have developed a Use Policy for the Play-Hookey Website.

If you have any requests for coverage in any topic under the heading of physics, chemistry, math, computer operation/repair/programming, electronics, or optics, please send an E-note indicating your interest to: webmaster@play-hookey.com. If you have an interest in some other subject, please feel free to indicate that as well. If I don't already have the required expertise available, I may still be able to locate it.

I hope you enjoy your visit to my site.