I want to learn how to make basic electronic circuits and follow circuit diagrams. For example, I want to be able to look at this and understand what’s going on. My background is in computer science and math. Does anyone have any good reccomendations for introductory books on this topic?
The Art of Electronics, by Horowitz and Hill, is a classic and far and away my favorite general circuits book. It’s somewhat dated in the digital-electronics sections but still very valuable for the sort of circuit you referenced. It’s a very different presentation from the usual algebra-heavy analyses of most undergraduate EE circuit texts, with lots of useful examples (and counterexamples!) so you might want to look at one of those as well.
“The Art of Electronics” by Horowitz and Hill is a bit advanced in places for a novice, but if you want to pick just one book, that would be my choice. I’m thinking that with your background, and maybe some poking around on the net when you get stuck, that you wouldn’t need much else.
The newsgroup sci.electronics.basics is a good resource when you do get stuck.
… and I see that someone else with faster fingers has the same recommendation.
Thanks for the suggestions, guys. Amazon just made $75.00. :eek:
At least it will look nice next to Art of Computer Programming. 
I know you’ve already ordered the book, friedo, but I’m going to chime in and add that IMHO it’ll be one of the best uses of $75 you can make if you’re interested in circuit design.
To add some new content to this post, I’ll also add that Winfield Hill, one of the book’s authors, is very active answering questions on sci.electronics.basics and sci.electronics.design. He is always very helpful and modest for someone who literally “wrote the book”.
The transformer has a primary winding and a center-tapped secondary winding. It efficiently reduces the AC voltage to a level that’s more “usable.” It also provides isolation.
D1 and D2 form a full wave rectifier. A rectifier converts AC to DC.
C1 reduces the ripple voltage on the output of the full wave rectifier.
At C1 you have an unregulated DC power supply, something very similar to a battery. But most people prefer a regulated supply. So the designer installed R1, D3, and TR1 to regulate the output voltage. (In other words, with a regulator the output voltage will stay fairly constant over a specified current range. It will also stay constant when the line voltage changes. Up to a point.)
D3 is a zener diode. When you inject a reversed-biased current through a zener, the voltage across it stays fairly constant. But to make it work you need a current limiting resistor – that’s the job of R1.
So D3 by itself is a regulated supply, but… it can’t source much current. That’s where TR1 comes in to play. TR1 is an NPN bipolar transistor configured as an emitter follower. The base-emitter junction maintains a voltage drop of around 0.6 V or so, thus the emitter “follows” the base. The base has a constant voltage on it (the output of the zener), thus the emitter also has a constant voltage on it. In this case, it would be the zener voltage – 0.6. But here’s the key: the transistor is able to source gobs of current to the load. The current enters the collector and exits the emitter.
BTW: The Art of Electronics is indeed an excellent book. But I would also recommend subscribing to one or more of the following magazines:
- Nuts and Volts
- Popular Electronics
- Circuit Cellar
The ARRL Handbook covers a surprisingly large range of topics, and assumes a level of theory that you should be comfortable with.