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One of the most frequently misunderstood concepts when introducing people to the fundamental aspects of technology are those of voltage and current. While many may look at a wall wart and see that they are provided a voltage of 12V at a current of 0.5A what do those numbers actually represent? In short: it’s all a matter of electrical charge.

Electrical charge is measured in coulombs (C) and represents the electrical charge exerted by 6.25151×10¹⁸ protons. Alternately it can be represented by the electrical charge exerted by -6.25151×10¹⁸electrons.

Voltage is a measure of the amount of work energy in Joules (J) required to move a unit of electrical charge (C) between the two points – mathematically V = J/C. Therefore voltage can be considered the electrical potential difference between any two points: the two poles of an electrical outlet, the Earth and a rain cloud, or even you and your friend. This is why when you connect the negative pole voltage of one voltage source to the positive pole of a second voltage source (like ganging two AA batteries in your remote control) the total voltages are added: you’ve essentially increased the amount of work required to move an electrical charge from the positive pole of the first source to the negative pole of the second source.

Current, on the other hand, is a measure of the rate of flow of electrical charge (C) through two points- mathematically I = C/s. This explains the old saying that “It’s not the voltage that kills you. It’s the current.” You can safely keep your hand on an operational Van de Graff generator operating at thousands of volts but minimal current. However, mishandling a car battery operating at a paltry 12 volts but delivering a whopping 600 Amps of current can hurt or kill you. Simply put: charge measures the rate at which electrical charge moves between two points of differing voltage potential, and too much electrical charge passing through an electrically incapable (organic) medium will cause a very bad day for said material. As for which way current actually flows? Well, that’s a subject for another time.

Consequently this explains the fundamental equation that every person dawdling in the electrical sciences needs to know: V = I x R otherwise known as Ohms law. This inverse proportionality shows that as current passes through a resistive load (R) it essentially slows down thus bunching up the electrical charge on the entry portion of the load and creating a greater electrical potential (voltage) across the terminals of the resistive element. Alternately, as the resistive load (R) is decreased the amount of the rate of electrical charge (current) drawn upon to maintain a requested electrical potential difference (voltage) is increased. This is why we don’t like shorts in our electrical circuits. R effectively becomes 0 resulting in a request for infinite current likely resulting in a blown power supply, tripped breaker, or blown fuse.

Now you know!

…and if you paid any attention to afternoon cartoons, Knowing is half the battle!


[Thanks to Armin Tamzarian]

The required criteria for qualifying something as “Geeky” or branding someone as a “Geek” are pretty relaxed. There are electronics geeks, computer geeks, RPG geeks, car geeks, beer geeks…you get the picture.

As such, the collective knowledge of geeks is so diverse that while you may be an expert in one thing, you can come across as a complete newbie in another. That knowledge barrier should not be something that deters you from expanding your geek lifestyle, rather it should be seen as a chance to learn something new.

Since we here at Geek Republic are gluttons for knowledge, we assume that our readers are too. So, to help you bridge the gap between what you know now and what you will be an expert in tomorrow, we are happy to introduce a new regular feature we call Geek Speak.

Periodically, our writers will put together a quick blurb on a topic that relates to one specific area of the geek universe. This might be the definition of a geek term, an explanation of a commonly misunderstood concept, or something in between.

Take a minute and give it a read – you might just discover your next geeky obsession.

Look for Geek Speak starting tomorrow!

This morning, Major Nelson announced a pricing increase for the Xbox Live! Gold service. These increases affect all packages, including 1 month, 3 month, and 12 month packages both in the US as well as abroad.

The service has not seen a price increase since its inception in 2002, and with all of the additional content provided over the years, Microsoft decided it was time to change the price structure. The new pricing that goes into effect November 1st looks like this:

• 1 Month membership – $2 increase from $7.99 to $9.99
• 3 Month membership – $5 increase from $19.99 to $24.99
• 12 Month membership – $10 increase from $49.99 to $59.99

Overall, the price increases are not terrible, however it would be nice to see some better protection against game hackers and system abusers if we’re paying even more for the service. Better response and policing via user complaints would be a nice way to see this extra money spent.

That said, I cannot remember paying even close to $50 for a year’s worth of Gold membership as long as I have owned my Xbox. Truth be told, I have only spent around $39 for 12 or 13-month membership cards in the past, so I don’t see the new pricing scheme hurting me all that much. It really pays to shop around and look for specials – if you look hard enough, I think you will be able to find 12-month membership cards for around $49.99 or less once the new pricing scheme takes effect.

[Majornelson.com via Forbes.com]

[EDIT]

It seems that Microsoft is allowing people to “lock in” an additional year of Live! service for $39.99 if they renew now at Xbox.com. If I were really desperate to save money, I suppose I would just buy a handful of subscription codes for the same price at Amazon and then stash them away until I needed them.

While BitTorrent might be all the rage, I’m a Usenet guy.

I am honestly not very patient when it comes to obtaining things I want, so waiting hours or days for downloads to complete has never been my strong suit. Aside from the original Napster, BitTorrent and similar P2P apps have never been something I have enjoyed using. Usenet however, is a completely different experience – one which I highly recommend.

You may or may not have heard of Usenet before, but it has likely been around longer than you have. In fact, the first spam message ever delivered was done so via Usenet. It’s the Internet’s oldest and best-kept “secret”. This is partly because Usenet is kind of like “Fight Club” in that the only real, yet unofficial rule is, “You do not talk about Usenet.”

I on the other hand do tell people about Usenet. However, I only do so provided I have deemed them technically capable enough to handle the task. This is really one of the main reasons why I think Usenet remains a little more obscure than most other online technology. While Usenet is not as complex as say, compiling your own Linux distro from scratch, there is definitely a learning curve that stretches beyond the patience and understanding of most people. I find that the benefits of Usenet far outweigh the cost and effort associated with using it.

The major highlight of Usenet is that there is virtually no waiting. You don’t have to wait hours for a slow download to complete. You don’t have to sit and hope that there are enough peers available to grab that old file you are looking for. When something is posted to Usenet, it’s there for good (almost). When you select a file that you want, you are able to download it as fast as your broadband connection can handle, provided you selected a good Usenet provider. Everything is “just there” – no waiting, no fuss…you just grab and go.

That said, if you are contemplating leaving the world of trackers and leechers behind, I will be more than happy to lead you to the path of enlightenment…

Continue reading “An Introduction to Usenet” »

Here is last week’s “Weekly Build” – sorry for the delay!

Recently, the enthusiast oriented builds we have put together have been relatively expensive, usually around the $1,000 mark. After seeing my article on the $500 PC for grandma, Jared became curious as to how cheaply you could build a machine but still be able to use it for gaming. I set out to see what kind of gaming performance you could squeeze out of $600. As it turns out, quite a bit.

Continue reading “Weekly Build – Gaming on the Cheap” »

Metasploit architect HD Moore has let it slip that he has discovered a major vulnerability affecting a wide range of Windows applications. This vulnerability, not unlike one patched in the Windows version of iTunes a few months ago affects around 40 applications including Windows Explorer, which is a major component of Windows.

He says he discovered this exploit while researching the Windows Shortcut bug that was recently the subject of an out of band patch by Microsoft.

Moore suggested a workaround, stating, “Users can block outbound SMB [by blocking TCP ports] 139 and 445, and disable the WebDAV client [in Windows] to prevent these flaws from being exploited from outside of their local network.”

[via ComputerWorld]

Matt shared this video with me, and though the mod itself is a few months old, I had to pass it on. It looks like a decent amount of work went into this Doom II mod, though I wish they would have tried recreating some of the maps as well. The mod is advertised as “MW2 for poor people” – I’m not sure about the “poor people” part, it just looks fun to me!

[MW2 Mod for Doom - Robbaz.com]

BoyGenius is reporting that there is code deep within iOS 4 that suggests the CDMA version of the iPhone and iPad is ready to be tested by carriers very soon.

This code allows certain units to bypass otherwise mandatory activation steps, allowing the use of the phone by partners and carriers for testing purposes without any hassles. The source cited in the article states that this sort of code always precedes the release of a new product and is promptly removed just before launch.

It should be noted that this is not a guarantee that this is the long-awaited Verizon iPhone, as Sprint’s network is also based on CDMA technology. Then again, who are we kidding?

Let’s just hope that this time around, Apple has a tighter grip on their testing units, so we don’t have a leak like the last time around…

[via BoyGeniusReport]

For this week’s build, I am going to piece together what I would likely buy if I were constructing a home media server. As a forewarning, I have been known to over-spec a machine from time to time, and this will likely be no exception. I like to ensure that my builds are future-resistant, as there is no such thing as future-proof, so you may feel that this machine has more power than you would want in your home media server. That’s totally fair – feel free to use my recommendations as a base on which to build, toning down my hardware choices to fit your needs.

For me, a home media server needs to fulfill several requirements. It must:

1. Provide ample storage with room for expansion
2. Provide ample power with room for upgrades
3. Be robust enough to last at least 5-7 years
4. Be reasonably quiet
5. Be somewhat attractive – I’m not looking for a Lian Li case here, but the computer should look fine sitting under my desk, or in a closet, should I so desire.
6. Finally, it should be relatively affordable

With these rules in mind, here is what I came up with, all for less than $1,200…

Continue reading “Weekly Build – A sub-$1,200 Home Media Server” »

While not the geekiest thing in the world, cleaning is something that has to be done.

One tool that I use to keep things tidy happens to be a Bissell SpotBot. I have a cat, and as cats are known to do, she enjoys leaving hairballs in all sorts of inconvenient places. The SpotBot is a miracle worker when it comes to cleaning up the aftermath. I fill it up, set it on the spot, hit “Surface Stain” and I walk away. The machine sprays, scrubs, and suctions off all the nasty stuff while I go about my other business. Anyone that has a pet or child under their care knows that stains on the carpet are inevitable, so I wholeheartedly recommend this machine to everyone.

Bissell SpotBot - The lazy man's steamer

That said, after 5 years of abuse, my SpotBot stopped spraying solution. I knew that something was up a while back when the manual attachment stopped spraying anything more than a trickle. The death knell came the other day after my cat spewed up what appeared to be a completely separate feline in various places throughout my house. The SpotBot stopped spraying altogether right as I started cleaning. The pump, it seemed, had given up the ghost.

Because I am a geek at heart, I will not let any electronically powered device I own hit the trash heap before I get a chance to take it apart. I thought that the pump was dead, but I wanted to ensure that it was not just a simple blockage or crimped hose.

A word of caution – This tutorial involves the disassembly of a consumer product that utilizes 120v A/C current. Taking this device apart not only voids your warranty, but it may also be dangerous. Exercise caution when working on this machine as it operates using water. As you may recall from childhood, electricity and water do not mix. For safety’s sake, at least unplug the SpotBot before working on it!

Taking the SpotBot apart is a pretty easy task. All you really need is a Phillips head screw driver and a few minutes. A pair of pliers will be useful later on when moving hose clamps.

Continue reading “Bissell SpotBot Pump Repair” »