Newbie-ish electronics question...

[MarkS]

I understand the role capacitors play in electronics and even understand the formulas involved. However, I have never understood when to choose a certain type of capacitor, and in some cases, the rating for the capacitor.

Case in point. I know that most ICs require, or its recommended that they have, bypass capacitors between the GND and VCC pins. On very rare occasion, the IC manufacturer will state the size of capacitor. More often than not, they don't. I'm not exactly sure how to derive the size of the capacitor from the data in the data sheet. I'm still learning to read data sheets and am having to teach myself, so that may be part of the problem. Something tells me trial and error play a part here, but I want to be sure. How can I tell if I should use a .1uf or 47uf or whatever capacitor. I know that I should know this, but alas, I don't. :(

Also, most engineers use polarized electrolytic capacitors for bypass applications. Why not use tantalum or an unpolarized disk capacitor? In any case, why use one type over the other? I have scoured introductory electronics texts for this information and it seems that without fail, they show the various formulas, explain what a farad is and describe the differences in capacitor types, but never explain when to use a particular type or why. This has got to be something that is taught. Components are just to expensive to play guessing games with.

Also, In the course of doing research for the project I'm building, I ran across some rather old information regarding solderless breadboards. The author of the text mentioned that breadboards should not be used in applications where frequencies approach or exceed 8MHz due to ringing. That's a problem for me because the project I'm doing, a MC68000-based robot controller, is going to be running at or above 8MHz. If I cannot use a solderless breadboard, what can I use or is this information outdated?

[MarkS]

After doing some more research, what little I can find online (an odd thing to say the least), I clearly need to go back to basics.

Can you guys give me a list of good introductory textbooks for electrical engineering? I do not want to go to college for this as I have no intention of making a career out of it, but I would like to learn the subject matter better.

I just find it amazing that I can understand the more complicated stuff, like logic and ICs and such, and yet somehow missed the truly important stuff like passive components and being able to read a data sheet.

[HarryBotter]

I understand the role capacitors play in electronics and even understand the formulas involved. However, I have never understood when to choose a certain type of capacitor, and in some cases, the rating for the capacitor.

Case in point. I know that most ICs require, or its recommended that they have, bypass capacitors between the GND and VCC pins. On very rare occasion, the IC manufacturer will state the size of capacitor. More often than not, they don't. I'm not exactly sure how to derive the size of the capacitor from the data in the data sheet. I'm still learning to read data sheets and am having to teach myself, so that may be part of the problem. Something tells me trial and error play a part here, but I want to be sure. How can I tell if I should use a .1uf or 47uf or whatever capacitor. I know that I should know this, but alas, I don't. :(

I'm with you on this subject. What little I know suggests that outside of timing applications cap sizing is more art than science. I've often played with sizing until it works. Perhaps someone who knows more can chime in.

Also, most engineers use polarized electrolytic capacitors for bypass applications. Why not use tantalum or an unpolarized disk capacitor? In any case, why use one type over the other? I have scoured introductory electronics texts for this information and it seems that without fail, they show the various formulas, explain what a farad is and describe the differences in capacitor types, but never explain when to use a particular type or why. This has got to be something that is taught. Components are just to expensive to play guessing games with.

Again, I'm not strong in this area but to the best of my knowledge electrolytic capacitors are used where higher capacitance is required.

Also, In the course of doing research for the project I'm building, I ran across some rather old information regarding solderless breadboards. The author of the text mentioned that breadboards should not be used in applications where frequencies approach or exceed 8MHz due to ringing. That's a problem for me because the project I'm doing, a MC68000-based robot controller, is going to be running at or above 8MHz. If I cannot use a solderless breadboard, what can I use or is this information outdated?

I've breadboarded 20MHz chips with no apparent problems.

[HarryBotter]

After doing some more research, what little I can find online (an odd thing to say the least), I clearly need to go back to basics.

Can you guys give me a list of good introductory textbooks for electrical engineering? I do not want to go to college for this as I have no intention of making a career out of it, but I would like to learn the subject matter better.


I started off in a position similar to you and found two books particularly helpful. One is very basic and the other at an intermediate level.

1. Getting Started in Electronics by Forest Mims III (Radio Shack)

2. Practical Electronics for Inventors by Paul Scherz

I've also got quite a few other books on the subject that I often reference if I'm stumped but none as good as these two.

Harry

[MarkS]

Thanks. Maybe some others will feel like chiming in as well. I've tried to buy those books from RadioShack, but the moment I open the cover, I put it back on the shelf. Most of them are hand written, or look that way, the drawings are hand drawn, the paper is that cheap newsprint type and is usually yellowed. It just doesn't look professional. But maybe I'm wrong though.

[HarryBotter]

Despite appearances it was the book that got me started in this hobby. Never judge a book by its cover. :p

Harry

[MarkS]

Despite appearances it was the book that got me started in this hobby. Never judge a book by its cover. :p

Harry

Or by the paper its written on. Or by the fact that they didn't know how to use a typewriter. Or... :D

I'll take another look at it next time I'm in RadioShack.

[MarkS]

This is where I'm at so far. I have a heck of a lot left to go!

http://i18.photobucket.com/albums/b106/mspeir/68000Schematic.jpg

[dporter]

Looks like you already have a good start. One source that I have used besides the books Harry mentioned is the solarbotics library. Here is a link http://www.solarbotics.net/library.html
from there go to "beam from the ground up" then click on "getting started with Beam" the site has a lot of information on passive components. I hope it helps.

[shimniok]

Funny thing, even though I have a b.s. in Computer Engineering (with plenty of time spent on analog circuits and caps), I didn't really learn anything that would help answer your question, except when dealing with charging and discharging times, as in, the RC circuit.

For what it's worth I found David Cook's "Intermediate Robot Building" quite useful in this regard (and others--great book, just got it). He goes into the cap thing a little bit... it isn't a full-on engineering reference but gives some good working knowledge for the hobbyists like us.

The section on IR detectors and developing a voltage controlled oscillator using a 74AC14(?) talks about tolerances for several different types of caps (some vary by as much as 20%, some by only a few %). For high freq timing naturally you'd want to use higher tolerance. He briefly mentions how size of the caps depend on the materials.

There are other sections that talk about discharge rates for different caps, and other sections that talk about where/when to use caps.

Added to the references provided, this would probably help fill in some of the blank areas. Hope this helps!