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.

Viking Modular Systems has announced the availability of its SATADIMM, an Enterprise Class SATA II Solid State Drive (SSD) in an industry-standard DDR3 240-pin DIMM form factor. The SATADIMM SSD derives its power from the 1.5V supply to the DIMM socket (operates from 1.25 – 3.3 vdc) and data transfer is enabled by using a standard SATA cable. New designs have the option of wiring the SATA through the DIMM socket so no external cable is required. The SATADIMM has built-in ARS-128 encryption for data protection and supports Trim commands. The different models include SLC (single-level cell) versions with a 25GB to 200GB range and MLC (multi-level cell) versions with a 50GB to 400GB range. The SATADIMM supports SATA 3Gb with sustained read/write speeds of 260MB/sec., plus sequential and random performance of 30,000 I/O operations per second.

A few of us have recently been playing around with thin client motherboards that Jim graciously donated. While I already have a project in mind for mine, I can’t get the thought of building a car computer out of my head, since these boards would be well-suited to the task.  Once I pay off my car, I may make my carputer a reality – until then, I figure why not dream on paper? Perhaps readers will get the same urge that I have, so here is a place for everyone to start.  Keep in mind that this system is not meant for performance, but to have just enough power to serve as your new front end.

ZOTAC NF610I-K-E LGA 775 NVIDIA GeForce 7050 NVIDIA nForce 610i Mini ITX Intel Motherboard
[$44.99 - Newegg]

When considering a motherboard for this build, less is more.  There really is not a need to have a massive amount of components built in.  My mantra is, “The less we have, the less power the board takes”.  Reviews of the board on Newegg are decent, but varied.  Many people report problems trying to power this board, though those users might be mistaken.  In fact, one reviewer confirmed that the board only used 48w at idle and 62w under load.

Intel Celeron 430 Conroe-L 1.8GHz 512KB L2 Cache LGA 775 35W Single-Core Processor BX80557430
[$40.99 - Newegg]

I felt that finding a CPU with low power consumption would be the best choice for the power supply I selected.  Plus, to exceed stated power loads that the board supports, one would have to use a 35w Celeron 420, but the 430 isn’t much different in that area.  You can laugh, but this time the Celeron takes the cake.

Asus Triton 75 CPU Fan For Intel LGA 775 & AMD Socket 754/939/940/AM2
[$49.99 - PC Planet]

Since this is going to be a full dash install, I figured there wouldn’t be the need for a heat sink with a fan.  I felt that a fan might cause excess noise that would not be too pleasant when positioned just inches away from you.

G.SKILL 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 533 (PC2 4200) System Memory Model F2-4200PHU2-2GBLA
[$49.99 - Newegg]

I honestly didn’t pick this RAM for any reason other than it having the heatsinks attached.  It was pretty much the first thing that I saw with 2x 1GB modules for a decent price.  Remember, this system is not geared towards performance, but 2GB should be enough to keep Windows moving along nicely.  (If you decide to go that route.)

Kingston SSDNow V+ Series SNVP325-S2B/64GB 2.5″ 64GB SATA II MLC Internal Solid State Drive (SSD)
[$189 - Newegg]

I picked this SSD for a few reasons.  No moving parts means higher shock resistance, a must have in a car.  However, I am still surprised by how little force the SSDs can take when operating.  This one has a higher non-operational max vibration resistance and also has low power consumption. (Though it really is about the same as any other SSD).  Again, low power is pretty key in this system.  You might want to still add in some sort of vibration resistant mounting just to be on the safe side.

PICOPSU-160-XT
[$49.50 - Mini-Box]

So when it comes down to running a tiny board and trying to fit it in a tiny space, you really need a tiny power supply.  No, make that a PICO power supply.  If you read the reviews on Newegg for the motherboard, you will have seen that at least 1 person had success with a PICO 200w.  Though I think this 160w should suffice it also provides 200w at it’s max.  This also does DC-DC conversion which, if you know anything about your car, is mandatory.

LITE-ON Slot Load CD/DVD Burner Black Slim SATA Model DL-8ATS
[$49.99 - Newegg]

I am unsure about using an optical drive in a moving system.  You should consider using some type of spring and rubber mounting system to ensure that you can avoid skipping and grinding on the disc.  I also consider this optional because many carputer builders skip it.  After all, won’t all your music be on a hard drive?  Of course, having a way to update items from disc might be nice as well.

Sharp 7″ Touchscreen TFT-LCD Panel
[$106.91 - GoodDeals]

This is the key component of any good car computer.  It provides the ability to see and interact with whatever software you have installed.  Take note of the web site’s instructions on how to wire this up in a car.  You will need to attach the cable labeled “light switch” to your positive battery lead in order for this to operate when the car is turned to ACC mode.

Now I know this probably leaves you with burning questions on how to piece it all together or what to install on it, but there are plenty of websites dedicated to carputers.  This is simply a list of a few suggestions on how you might piece one together.  In total, all of the parts listed clock in at just under $600 before shipping, and I feel it would be a great way to get somebody started on a build.  A few extra items that might be needed, depending on what you want it to do, would be a GPS unit and perhaps some hardware to use all six channels of sound coming out of the motherboard.

Comments? Suggestions?

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” »

I sat down late last night playing with all sorts of digital chad trying to determine the first winners to our gaming giveaway.  Luckily I was able to turn to a random number generator to not only pick the winners but their prizes.

Congratulations go to Twitter users Vermontffl and the_Bigandtasty who won Dead or Alive Extreme 2 and College Hoops 2k6 respectively.

Now don’t fret, this is your chance to get a SECOND entry in (or sign up for the first time).  Just visit the contest’s main page for the same instructions as before and in 2 weeks time I will randomly pick winners and prizes again.

Every electronics workbench needs a power supply. Depending on your experience and type of projects, you might even need multiple power supplies. Converting a PC power supply to bench use is one option, but I needed something smaller with variable output voltage. A variable output of 0-15 vdc @ 1 amp and a built in voltmeter, to more more specific. So off to eBay I went looking for a project case, panel mount voltmeter and some other small parts. One of my eBay searches turned up a new tattoo power supply for $6. Well here was my case, digital voltmeter, switches and power cord for a fraction of the price of the individual parts. If I was lucky, some of the internal parts could also be used.

Continue reading “A Mini Benchtop Power Supply” »

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]