Circuit Troubleshooting For Dummies

Once upon a time, I wrote down some troubleshooting steps for circuit builds in my EE labs. After some frustration I’d had with circuits that didn’t work, Teaching Assistants who refused to offer firm troubleshooting suggestions, etc., I compiled this list of things to try when I was too frustrated to think anymore.

In light of the previous discussion about Troubleshooting Methodologies, I offer these suggestions to other EE students — or anyone messing around with circuits for projects or entertainment. These are really simple steps, but sometimes the simple solution goes out the door when it’s one hour before your project is due and the blinkenlights just ain’t blinkin’. Hope they help you the way they’ve helped me.

1. Verify component placement. Where’s Pin 1 on your component? Are all the pins in the breadboard? Are all the pins *good* – no broken or bent pins that don’t make a firm connection? Are your transistors placed correctly? Are your diodes in the right direction?

2. Verify connections. Use the shortest possible wire for neater circuits. Are all your wires connected at both ends? Verify that all connections are wired from point A to point B correctly, and are in the right places. Check each wire twice against your schematic or your notes to make sure it’s in the correct position.

3. Verify loops. Is everything closed? Are your lines to GND and your power placed correctly? How about your lines to your input signal and meters and scopes and analyzers?

4. Check your cables. Your scope probes need to connect to GND as well. Check every cable twice.

If your circuit still isn’t working after these steps and troubleshooting takes longer than 15 minutes, NAG YOUR T.A.! That’s what they’re there for, and if they don’t seem helpful at first, nag them until you get some sort of resolution. They’re grad students, so they can take it!

Did I miss anything? Drop me an email or leave a comment and I’ll modify this post for future reference.

How To Use A Slide Rule

Listen, we’ve only got four and a half years until the world ends, and if that doesn’t pan out, it’s just a matter of time before some virus strain (or alien culture or robot revolution or our own stupidity) destroys society as we know it. Isn’t it time you made sure your low-tech skills were polished?

With that in mind, here’s your first Apocalyptic Preparation assignment: learn how to use a slide rule!

I’ve always thought of slide rules as gadgets or puzzles, not as serious calculation tools. I keep my eye out for them at garage and estate sales (and once missed purchasing one by five minutes; curses! Foiled again!) and even purchased a cheap plastic and paper slide rule which I might still have in the Lair somewhere. That said, learning to use a slide rule has been on the Zora List for some time.

Over at the Museum of HP Calculators, there’s a page of Basic Slide Rule Instructions. Keen! Now, I’ll be able to do simple trig without my TI-89! This site also has links to photos of various slide rules, and to a page with some slide rule history.

Got a slide rule? Email me a photo at and share!

Photogeeks: Digital Photography School and PSDTUTS

I’ll admit to being a complete n00b when it comes to all things involving image hacking. I tried Photoshop, but it seems unwieldy to me, and I have to say the same for GIMP. In fact, most of my image editing needs of late have been satisfied by Paint.NET, though I do use Photoshop Elements to take some of my photos to the next level.

That said, you folks who *are* into digital photography and image editing may find the following information interesting.

Digital Photography School. I first came across Darren Rowse’s work when searching the web for blog info; I didn’t find out until later that this site came first! DPS is loaded with digital photography stuff. The resources page includes info about everything from “Photography Tips For Beginners” to making money from your images.

The blog has *tons* of tips. I mean it. Need a little more structure? Take a look at the Weekly Assignments. That’s right – homework! For those seeking more of a connection with other photographers and editors, check out the forums.

PSDTUTS. Once you’ve taken your photos, how do you make them look good? Visit the PSDTUTS tutorial site and get “spoonfed Photoshop”. This site has innumerable tips and tricks for working with your digital images, as well as news and developments in the Photoshop-related world.

While there’s plenty of free content, a few of the goodies are only available if you buy a membership, but in their defense, it’s only $9 a month. (That’s cheaper than MMORPGs, and with *actual* skill leveling instead of imaginary mastery!) They’ve separated the RSS feeds out so you can subscribe to just the tutorials if you want, which is smart. And if you’re already talented enough with Photoshop that you don’t need to visit their tutorials, write one of your own and submit it to this site for pay!

No matter what your level of skill, these sites probably have something new to offer you. If they help (or hinder) you, drop me a line at and let me know how!

Your First Welding Project is over at Lady Ada’s

Last week, I was sitting at an Engineering Showcase at the university with my rocket buddies and one of them (thanks, I.O.!) mentioned “Lady Ada”. I’ll chat more about her soon, but in the meantime, browse her site for all kinds of cool goodies.

If you’re looking for the first project to try with your new TechShop membership (or in the garage of your trusty friend with welding tools), check out Lady Ada’s Quickie Project, a DIY bike stand. Her instructions are clear and concise, and you should be able to work through them without too much difficulty. (And if you do have difficulties, which we all occasionally do, check out the forums.

Interested in more posts like this one? Send an email to or use the handy form on the Contact page.

5 Ways To Have Fun With Mathematics

This is the first guest post on .51, and it comes from Alex McFerron, a mathematics and computer science theory hobbyist (that’s right; Alex does this stuff for *fun*!) who answered my call for more math here on the site.

Thanks, Alex!

Here are five ways to have fun with mathematics right now, without having to review too much of what you’ve forgotten since school.

1. Start a puzzle club.

Logic puzzles, the kind where you break codes, or other interview type puzzles are fun when a job at Google isn’t at stake! Kick back with your friends at a coffee shop or your house and try to figure out puzzles together. There are a lot of puzzle games that you can buy to “mix it up”. Try the harder mathematics puzzles as well as the more fun wooden or metal puzzles.

2. Check out combinatorics, graph theory, and number theory.

These topics do not require a lot of math background. You could be doing research level problems with just a high school math education. These topics do require mathematical sophistication but you don’t need an undergraduate math degree or even a strong understanding of anything but algebra, geometry, and pre-calculus. A lot of the problems are similar to logic problems. For example, how many ways can six people be arranged at a table? You can think about problems like that one, and how to prove it, then read a little combinatorics. Number theory asks questions like, how do you know there are an infinite amount of prime numbers?

3. Boot up your system.

Use your computer to help answer questions you might have or to help find conjectures. This is called experimental mathematics. If you have programming skills, then you can take a mathematics question (aka conjecture) and try to find patterns to answer it. I recommend getting this book and using it as well as your computer skills to answer questions.

4. Take a math class.

If you’ve been working for awhile and haven’t been back to school in years, enroll in a night class. Take introductory algebra or calculus. Community colleges often have basic classes and good teachers to boot. For fun, I went and took trigonometry again at a college and I had a blast because I really didn’t feel any pressure and I was able to just enjoy it.

5. Hire a math tutor to help you read a mathematics book that is too hard for you.

Some math tutors are starving graduate students and do not charge much money. I have done this for as little as $20 an hour. I made a great friend *and*had a lot of fun reading math books that were otherwise too difficult.


–Submitted to .51 by Alex McFerron.

Got feedback? Drop a line with your comments to, or use the handy form on the Contact page.

How-To: 5 Ways to be a Car Geek

It never ceases to amaze me how often I miss a simple comparison across technical boundaries. In this case, as someone who will happily unplug a computer, open it up and tinker around blindly with a screwdriver, I still freak a little when my car makes a weird noise.

Which got me to thinking: what if I approached my car the same way I approach my computers? With that goal in mind, I’ve put together the following list of 5 ways one could begin to be a car geek.

1. Read the technical manual for your car.

I’m not talking about the owner’s manual and the uninformative booklets that come with a new car and encourage you to take the car back to the dealership or the mechanic for every little problem. I mean the Chilton or Haynes manual that breaks things down into little steps and describes how to perform simple and advanced repair tasks. The one I’ve got covers routine maintenance as well as a total engine rebuild, and everything in between, complete with diagrams, images, and step-by-step instructions. And once I opened it, I realized it’s just like any other technical manual I’ve ever read. Maybe you don’t understand the complete workings of the internal combustion engine, BUT if you can read the entire O’Reilly library on frickin’ PHP (or whatever is your geek skill of choice), you can grok how certain parts of your car are inter-related.

2. Put your web surfing skills to automotive use.

Do a web search of typical car emergencies, and have a plan of attack for when it happens to your car. Car doesn’t start? Look into common symptoms. Oil light came on? Do a search for your car model and see if it’s really a problem or some kind of bug. [Editor's Note: If your oil light comes on, the first thing you should do is pull over and check the oil. Do your web research later!] Heard a weird hissing gurgling noise? Make a list of search terms that describe the problem, then search to see if it really is, say, a water pump issue.

When you hear about someone else’s car problems, find out how that might be applied to your model of car and come up with plans A and B if it happens to you. Find a users group or mailing list for your car, and “listen” in for a while, just like you would on any other mailing list. This builds up a technical arsenal for your car the same way you’d have a list of things to try with your computer or with a programming problem.

3. Keep a decent set of tools in the trunk.

Once upon a time, I got a flat tire and popped the trunk only to discover that the tire iron didn’t fit my tire bolts. Don’t let that happen to you! Here’s a starter list:

  • a tire iron that actually fits
  • a decent and sturdy car jack that has been tested on a lazy Saturday when it *isn’t* an emergency
  • an adjustable wrench

Add a few rags and a pair of decent gloves so if you have to get under the hood, you can maneuver into the tight spots and not get yourself too greasy. Once you’ve added a few skills to your list of tasks that you can perform on your own car, add the necessary tools to your “road kit”.

4. Do your own low end maintenance.

Start with something small, like changing the wipers or brake lights, or checking and maintaining the right air pressure in your tires. Then work your way up to changing your own oil. Before you know it, you’ll be able to sub out battery cables if they look a little worn out. Just remember to read up on the problem first to make sure you’ve got a good plan of attack that will avoid any common pitfalls (e.g., reconnecting your spark plug cables in the proper order, etc.), then give it a shot.

5. When you *do* have to go to the mechanic, relax.

You’ve done your homework, and with knowledge comes confidence. How many times have you gone to the mechanic and just trusted what you were told was the problem? Well, now you’ll have more information *before* you go to the shop. The more you know about how your car is supposed to work, the better you’ll feel when it comes time to get work done and you have to pay someone to do it.

Think of this as the equivalent of running over to Best Buy to get some minor computer part and some smirky salesperson tries to tell you that your complete system is hosed and you need to buy a new Gateway laptop. You’d tell him thanks, but no thanks (or beat it, kid, you’re bothering me). You wouldn’t be uncomfortable because you *know* what you need and how it works. If you’ve got a mechanic who (a) will answer your questions without being condescending, and (b) can relate the problem to something else about the car that you already understand, you’ll feel much better about the whole deal. If your mechanic doesn’t do that, get another mechanic! If it helps, picture that mechanic in a Geek Squad outfit trying to sell you some virus scanning software for your Linux box.

Now, there are *true* car geeks out there. You who drive a thirty year old car because you rebuilt it yourself, or drive something brand spanking new because you had a hand in its design – my hat is off to you. If I’ve missed any starting steps, please let me know. I’m off to read the Haynes manual on my Tercel, because it looks like I’ve got a little hacking to do. Drop me a line at and let me know how things go with your car hacking.