Back to Basics: Ohms Law

During last night’s Open Hack Night, while trying to explain things like how transistors and mosfets work, it was discussed that maybe taking a step back and outlining some of the basics of electronics would be beneficial to everyone. So I decided to start with Ohms Law.

There are 3 things that Ohms Law deals with, and they are all related to each other. Those things are Voltage, Current and Resistance.

Voltage is measured in… well Volts of course!

Current is measured in Amperes.

Resistance is measured in Ohms! Named after this guy who put a bunch of work in discovering resistive properties electricity, and apparently came up with this relationship known as Ohms Law. Anyhoo.

I like analogy’s to help me relate things that I know, against things I don’t know. So everyone’s favorite analogy of electricity is water. Some will argue this topic to death, but for my purpose I’m sticking to it.

Voltage — So Voltage is actually a potential concept, think of a large water tank on the top of a hill and a small pipe coming out of the bottom. The difference between what is coming out of the pipe versus the pressure in the tank is the potential voltage. So voltage is the pressure.

Current — This would be the volume of water pushed through that pipe by the voltage (pressure) and would refer to the quantity of water flowing through it.

Resistance — So this would be the pipe its self. The larger the pipe (lower resistance), the easier current can flow through, thus having more current. The smaller the pipe (higher resistance), the harder it is for the current to flow through the pipe, yielding less water.

We’re really excited to announce that Baltimore Hackerspace has moved to a new location and we would like you to come help us celebrate. Come socialize, learn and check out the facility. We will have our projects on display and will be doing a couple workshops. There is also a rumor that there may be food!

If you are attending I invite you to RSVP so we can get an idea of how many people are coming.

http://www.meetup.com/Baltimore-Hackerspace/events/89508782/

When: November 17th, 2012
Time: Noon – whenever
Where: 6410 Landay Ave. Baltimore MD 21237 MAP

Class – Getting Bootstrapped with Git and GitHub

*** UPDATE ** This event has been canceled. Sorry everyone. We’ll be having Open Hack night instead.

Interested in getting started with Git? Curious about what’s so great about this DVCS stuff? Have no idea was DVCS is? Join us for an awesome night of Git and GitHub and get bootstrapped. Jared from GitHub (@ShepBook) will be presenting and will be hanging around to answer your questions!

Wed, November 7th, 2012. 7:00 pm.

Limited space available, so please register at http://www.meetup.com/Baltimore-Hackerspace/events/88080042/

We built, We raced, We lost

It took a lot of hard work to get the kart ready in time for the PPPRS event at Maker Faire NYC 2012. But we made it!

Needless to say, we learned a lot. Mainly to get started a little earlier — and not wait until 2am the night before to get the kart moving.

Burnt Mosfets, burnt motors and broken wheels later we made it back home to ponder the next one. Here’s a video showing some of the races, we had fun.

The little gerber viewer that could!

Of course I’m talking about gerbv! For those of you who don’t know, gerbv is a free Gerber or RS-274X viewer that comes from the gEDA Project. It’s free, it’s open source, it’s cross platform… (quick link to windows version download here) and that’s awesome.

So, why do you care? Well, if you are building your own circuits and want to get a PCB made then usually the format you’ll need to export your design into is a gerber. The reason you should grab gerbv is to double check for errors. When you design a PCB in your favorite circuit layout tool, whether it be Eagle, Altium, or my favorite DipTrace, you should double check for errors.