Category: Analog Electronics

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Analog Electronics Life Renewable Energy

Inventions for the future

I was talking to my friend the other day about ways to become rich and famous. Surprisingly, blogging was not on the list :-). The best I could come up with for an engineer like me was to invent something and sell it. Even better, invent one thing, manufacture it, use the profits to invent something else, and so on.

Then I started thinking about it and the thoughts of money and fame kind of melted away. Sure, that’d be nice, but what does the world really need invented? What could change the world? What could start the next revolution (i.e. industrial, technological, etc)? Where is the future taking us and most importantly where are WE taking the future?

  1. A new method of propulsion for air travel
    • There is no doubt that the world is dependent on fossil fuels. And for all the talk of renewable energy and even all the progress of it, there are still some things that will be dependent on fuel. In 2004 alone 7.2% of the oil consumption came from air travel/military airplanes. That same link also mentions that there are some other ideas in the work for using hydrogen, but that is a ways off (and still has a significant environmental impact). I have also seen biofuel options, and even the government is in on the idea. Unfortunately, oil and biofuel are the most energy dense option option. Until we have significant advances in energy technologies, using fuel cells or batteries will not be possible. Perhaps renewable energy for travel is not viable by air at all? Maybe electric trains or boats will be the most efficient way, but these things need to be discovered. Of course, there have already been some…um…interesting ideas.
  2. A new method for energy storage
    • There’s a lot of chatter about this lately (see above). Batteries just don’t seem to be doing the job they need to, so people are looking to other options. In fact, the doozy of an article I reference happens to be on this very subject (hint: it’s not a positive article).
    • We need to develop high efficiency, low cost storage devices because renewable energy (solar, wind, geothermal, cow farts, etc) do us no good unless we can transport that power. We could try to make hydrogen, but that’s not exactly the safest way to transport energy. Long term, I think electricity is our best bet in terms of delivering power to devices, even if that’s not the safest option either (I’m not so sure there will be one). Some might say I’m a little biased on the whole idea of electricity though. To electricity’s benefit, a lot of the infrastructure is in place, as are the devices (i.e. electric motors).
  3. A new method for space travel
    • OK, maybe I’ve watched Star Trek and Star Wars once or twice in my life. But just because I have seen that and dreamed about it doesn’t mean it’s not a good idea. Long term, the earth isn’t going to cut it for us. Either some wacko will finally set off a bunch of nukes, we won’t figure out a solution to global warming, we’ll run out of non-oil natural resources or medical technology will extend life to the point where population is unreasonable. So we’ll have to get out there and poke around, find a new hang out. It’s not exactly a short bike ride, either: The closest star system is Alpha Centuri, a short 4.22 light years away. What we need is some way to either approach the speed of light or find another way around (wormholes, improbability drives, etc). The point remains, the whole take a bunch of rocket feul and shove it out the back of a space ship just isn’t cutting it anymore. I like the idea of ion engines, but we need to see some more progress.
  4. A universal translator
    • Every time I think about world events, I think how lucky I am that I speak English. There’s no other language in the world that people are more eager to learn. I mean, I worked at an international company for 2 years and only learned 4 words in their native language! (hello, thank you, beer, please) That includes spending 8 weeks in Korea bumbling around hoping others would speak English (they did).
    • Imagine it though. Imagine if there was a way that all people could instantly communicate at least on a low level (aside from hand gestures). It would open new pathways to business, travel and most importantly international relations (especially tense ones). I had heard rumors that there were some people working on such a device, but could not find any further information on it. If this ever became commercially viable, it would change the world…and then Rosetta Stone would get very angry.
  5. Memory/Cognitive enhancers
    • This could come in one of two forms. The first would be a drug/supplement induced type, where we take what the human mind has to offer and then improve it by offering more resources (oxygen, nutrients, etc) or whereby we stimulate  the memory center to work harder or faster (think caffeine, but healthier, hopefully). The other method would be more radical, but I could see becoming a viable option in the future. That would be neural implants (think matrix) whereby our brains interact with computers/electronics. There are tons and tons of ethics questions surrounding such a device, but it will be possible someday. I envision this kind of device allowing ease of access to information and even better access to communication between people hooked to such as system. Who needs a universal translator when you speak binary?

Sure, there’s other stuff that would be great to invent or even just see invented. Even better, there’s some really silly ideas out there that are fun to laugh about. I think it’s important to dream about these kinds of things though. For those interested, I would highly suggest that you look into the work of futurists such as Ray Kurzweil or inventor Dean Kamen. Both of these guys have driven some amazing inventions and will continue to do so. Plus Kurzweil has been pretty accurate on his predictions before, so trying to fulfill some of his predictions probably isn’t a bad idea if you want to invent something. I’ll let you know when I’ve come up with something.

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Analog Electronics Life Work

Analog Definition

I have been working on a doozy of a blog post for about a week now. It’s almost there and I will definitely release it this week. However, in the interim I have been thinking about my blog and my (analog) life and realize I’ve never really defined it for many people. And like some others, I get questions about it:

What is Analog? What is my definition of Analog?

Analog is everywhere. Analog is the opposite of digital. It is continuous. It is real. Analog are the sights we see and the sounds we hear. Analog is the beauty of a symphony and the complexity of a transistor.

OK, maybe that last part is a little out there. But let’s get down to it. When I say that I am an analog engineer, what does that mean? It means that I work on devices that are primarily in the analog realm. As an example: If I made an electronic circuit that counted to five, there would be many different ways to do it. However, I think there are two basic definitions when it comes to circuits. I could create a circuit that counts 1, 2, 3, 4, 5. This would be a digital circuit, because there are only 5 values, and they are not continuous. However, an analog circuit would count something more like 1.00000, 1.00001, 1.00002, 1.00003… 4.99999, 5.00000. There would technically be an infinite amount of information in between 1 and 5, and the precision would be infinitely more that what I have shown. However, as humans, we decide to define numbers to explain the world in finite amounts, either because of time constraints (it would take a very long time to count otherwise) or because of simplicity (we all learn to count to ten because most of us have ten fingers).

Alright, so that’s a good start. Analog = continuous, digital = not continuous.

So why did I choose analog? Well to be completely honest, I didn’t. I got lucky and was presented with an opportunity to work on analog. It seemed to fit many of my goals and it was a welcome change of scenery, not to mention that analog engineers are pretty scarce (and therefore being one has inherent value). However, the best part is that every day I discover something new about it. The weirdest thing I find though, is that I am working on problems that have been around for 50 years. There are people working on the newest digital devices at the bleeding edge of technology, but that stuff doesn’t really interest me. I like the problems that have been around because there need to be more succinct and elegant solutions. Plus, I think the most interesting stuff actually happens when you take all that digital information in the form of 1’s and 0’s and try and put it back into analog. Or vice versa, getting analog signals into digital form isn’t easy either.

Ok, one last example then I’m done. Here’s a decent way to think about what I do. Say you have an iPod. You hit the play button to turn on your favorite track. What happens? Well to start with, all the digital electronics pulls the data off of the flash memory. Then it says: “OK, I have 1’s and 0’s, now what?”. It pushes these 1’s and 0’s into a digital to analog converter (DAC). Now it’s a tiny little sound wave (but an analog signal, yay!). Ok, so now the iPod says “What volume did they want?”. So it takes the volume you select and it amplifies the signal so it will come out of your headphones at the proper volume (not too loud, kids) and you can walk down the street boppin and groovin. Everything from the DAC forward, is similar to what I work on (I don’t do audio, but the ideas are the same).

So there’s my analog definition. I hope it helps and I will reference and revise this post as my career and life change. Cheers!

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Analog Electronics Life Work

Should I get a PE license?

I’ve never thought of myself as particularly upwards mobile in my career (yet). I’m actually very happy where I am right now, learning as much as I can and progressing through the rigorous on the job learning and tribulations I’ve been experiencing so far. However, the sign of a good career path is one where you are surrounded by people who both push you and are good role models for you. I am lucky to be in such a situation and as such, am thinking about getting my Professional Engineer (PE) certification.

This is actually not as common for electrical engineers as it is for other engineering disciplines. For example, most civil engineers can’t touch anything until they have obtained their certification. With the recent bridge disaster in Minneapolis, I can’t say I really object to this. However, just today I was talking with 2 of the 4 PEs at my company, both of whom happen to be in my group, and both were very convincing on reasons why it’d be good for a young engineer to take the Fundamentals of Engineering (or FE, the qualifying exam).

  1. Use it or lose it
    • Even the sites about the FE exam say it: The sooner you take the exam after school, the higher likelihood of passing it. It makes sense. You’re closer to your exam-taking, all-night-cramming, super-stressed-out days of engineering school. Once you enter the practically driven world of the workplace (as opposed to “academically driven”, to put it nicely), you lose some of those skills and they are hard to get back.
  2. Self-employment
    • Aside from the bridge builders and the others who need a PE to sign off on stuff, working as a consultant or a contractor sometimes requires that you have a PE (as an electrical engineer). As I’ve written before, self-employment is an eventual goal of mine, so that’s another reason to consider this.
    • Many power companies actually require that their engineers have their PE. This is because they work “directly for the people” and because the engineers sometimes actually work as contractors for the power company. Oh, and the stuff they make can really kill people quickly, forgot about that.
  3. Feather in the hat
    • As one of the two engineers I was talking to put it, “If you have 100 electrical engineers in a room and ask who has a PE, maybe two will step forward”. Great point. This is a way to show that you’re capable of achieving AND that you’re willing to stand behind your designs. As I really love reading about (and how this blog kind of came to be), careers these days are all about branding and a PE just helps strengthen your brand.

I could tell myself I’d wait until after grad school, but let’s be honest: grad school is about graduating and getting the paper. I think any time I take this exam, I would need to study pretty far in advance. So why not now?

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Analog Electronics Renewable Energy Supply Chain

LED supply chain

http://www.edn.com/article/CA6571020.html?nid=2437&rid=2069959399

As LED lighting and nearly all aspects of energy saving and/or renewable energy come into focus in the real world, we need to keep an eye on the economics of it all. You know the big players are. Big attention means big money and as you can see, lots of people want a slice of the action.

A quick synopsis of the above article could be: LEDs don’t work on their own…people need to buy other stuff. I have already written about one such component, the LED driver, in the past few weeks. Other than touching on drivers, the article also mentions other aspects of LED design including heat management, logic control and LED internals. Each of these parts of the whole design will need to ramp production in order to introduce economies of scale on each part level. The most striking number from the above article is that for every dollar spent on a LED (in this case a HB LED, used in commercial and residential lighting), the user must also spend $2-5 on auxillary components. This means that as the use of LEDs increase, so shall the semiconductor interest in driving those LEDs.

Another sign of this is chip makers entering traditionally non-lucrative markets. National Semiconductor has recently added a power management line of silicon aimed at taming the fickle nature of solar panels. When Nat’l enters the fray, you know they have projected some serious growth. So while my optimism for the entire subject of solar power is restrained, things like the new solar chips and the LED articles mentioned above make me happy. Hopefully we’ll see more news like this soon.

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Analog Electronics Life

My volunteer idea

I’ve been thinking a lot about learning lately. I’d say the amount I’m still learning at work has a good amount to do with it. But I’ve been brainstorming a charity I would like to start.

I would like to start a charity that goes around to schools and promotes science and engineering to lower and middle income schools.

Not because I’ve been reading about how the country will be hurt by less engineers coming out of our schools. To be completely honest, that would work in my favor because I would be more rare and therefore more valuable. But really I want others to experience engineering. I want others to be curious about the world. I want to inspire some kid that’s going to create the space shuttle that makes it to Mars.

At first I was thinking that my idea was original. It wasn’t. A lot of companies have some great programs in place for this sort of thing. But what drives me here is that most programs I have found are more localized. Some programs are national, but they aren’t educational programs so much as they are activities (as they should be, hands on is crucial). I was also thinking possibly this excitement could be generated in kids from books. But there are already these out there too, some more subtle than others. I even read some of these when I was a kid and perhaps this is why I became an engineer in the first place.

What I envision is a national network of engineers who are “dealt” out to schools to present to children in their classrooms. These should be hands on or at least exciting presentations, similar to a “career day” where kids’ parents come in and tell what they do. It needs to be more exciting though. Most importantly, the kids MUST realize why they need to learn certain things in school and how they apply in real life. I think back to all the things I learned and subsequently forgot because I thought it wasn’t going to be necessary in “real life”. I’m sure this has happened to everyone. But you need to plant that seed so kids get excited about learning the math and the science that we always hear about faltering, so they know what they have to do to reach an eventual goal of inventing something or helping people with science.

When I was thinking that a book might be the correct route, I began to outline the ideas I had for topics. I think they would be relevant as a framework for a volunteer speaking in front of a classroom. Here are some of those initial ideas:

  1. Why is great about engineering? What do engineers do?
    1. Example products are a great way to excite kids because it’s something tangible. If you show them the latest iPhone and tell them about all the different components inside and how they need to be made, kids will listen. If you tell them about how a bridge is made and how much weight they can support (preferably in units of #’s of elephants), they will listen. When you tell them that you can create an artificial limb for someone to walk again, they will listen. Stress all the different types of engineering and science and you will pique a lot of individual interests.
    2. Stress the fact that they can change the world.
    3. Sure, most engineers will tell you that there’s a lot of stuff that isn’t great about being an engineer or a scientist, but that’s not how you inspire people. You don’t tell a bunch of aspiring doctors how they’ll have to deal HMOs, do you? You don’t talk to aspiring lawyers about the boredom and monotony of reading legal cases for civil suits, do you? In this case, you tell them about designing and being creative and making things that will help the world. All the things that all of us aspire to do every day, even if we don’t get to. Extra points to the presenter who gives ideas to kids on how to inspire their creativity.
  2. What do you need to know to be an engineer?
    1. Math
      • This is probably one of the hardest subjects in school based solely on the fact that it is abstract. I remember the day that my calculus teacher started talking about a math theorem in terms of cars. Or the day I found out what a fourier transform really represented instead of the math you had to do in order to get a solution. Abstraction is something that is not learned until later in life and kids need reinforcement on why math is important. Hook them young and you’ll have a math fan for life (the other option is to force them to learn math at first and hope they appreciate it later…doesn’t work)
    2. Science
      • This is the obvious one and probably allows for the most demonstrations that will excite kids. It would also be a good opportunity to tie in the different types of engineering.
    3. Business
      • This is definitely something that engineers need but would really be a better way to work in other subjects that might not be thought of as necessary for aspiring scientists and engineers. Even English and history could be worked in as being necessary for writing and context. The idea would be to stress that all subjects are important in some way or another.
  3. Where can you learn more?
    1. Your parents/Your teachers/Your heroes
      • Stress good role models to kids. This is done in many avenues but cannot be done enough. Stop kids idolizing Pacman Jones, introduce them to Dean Kamen or Stephen Hawking. Make sure they know that they can learn a lot from their teachers and to utilize them any way possible.
    2. Wikipedia/Books/The internet
      • Curiosity didn’t kill the cat. It taught him something dangerous and then he was careless with it. Teaching kids to be curious is very important and stressing that they will need to teach themselves is even more important. Teaching oneself and doing useful research should be a class unto itself in college, let alone elementary/middle/high school.
    3. Each other
      • The most important thing that any aspiring scientist/engineer can do is to try something out themselves. Build a radio with a friend. Build a race car with a friend. Build a treehouse with a friend. Learn how to work well with others and don’t ever be afraid of failing. You will learn the most in your life from the things you don’t do right the first time.

Finally, in order to get this type of volunteer opportunity off the ground I think there would be some initial hurdles to get over:

  1. Finding volunteers
    • One of the problems with having engineers speak in front of kids is that…they’re engineers. Not so much the awkwardness factor (although I’m sure that could be a problem), but really the “having-a-day-job” factor. You’d have to ask engineers to take time out of their day to go speak at a school That could prove difficult.
    • Also, there would have to be a screening process, as bad as it sounds. A presentation that is boring in front of kids could have the opposite effect. Perhaps just a trial run for the volunteers to make sure they’re keeping kids engaged.
  2. Finding acceptance in schools
    • The target schools here would be middle to lower income. To be perfectly honest, I have no idea how receptive they would be to this idea, but there would definitely need to be planning.
    • Another hurdle would be maintaining contact. Say a volunteer goes to speak to kids once a year, then all the schools in an area would be covered pretty quickly. There would need to be an on-going effort with schools to maintain a program.
  3. Finding funding
    • Everything costs money. And similar to the point made above, engineers have day jobs, so someone would have to coordinate everything. That means assistants/interns/whoever and office supplies cost money. There could be a nominal fee to bring these people into schools, but then that contradicts with the above idea of middle-low income schools that might not have the funding. Perhaps there could be a corporate pairing (“JFK middle school loves Analog Devices!” t-shirts?) or perhaps with other professional organizations.
  4. Finding time
    • This is more of a personal thing. Sure I’d love to start this charity/volunteer thing, but it’s going to take some time to hash out and start up. If you’d like to help, let me know.
Categories
Analog Electronics Renewable Energy

Creating (sorta) simple LED lighting for your home

An article about a new LED controller from Linear Technologies was the inspiration for this post. I decided upon seeing this article that it could be a good way to talk about a theoretical LED lighting scheme in your theoretical DC powered home.

One key I’ve learned to engineering is not trying to re-invent the wheel every time you start a project. In that spirit, I thought I would show case a new Linear Tech part that would fit well into an all DC powered home.

The basic idea of this circuit is to create a buck-boost converter, in order to pump more voltage into an array of power hungry (yet hopefully efficient) LEDs. Also there are other options on the chip to allow it to be even more versatile and act as a buck, boost, flyback or SEPIC, depending on setup and peripherals. Even though the listed applications are more for driving headlights and industrial applications (powering detection LEDs on an assembly line and then using a photo detector to determine changes), I believe this could work in a house wired with DC power in the walls. I believe a

Looking at the schematic on the EDN site, also directly linked here,  you can see that there are some external components that are required for this part, but are mostly in the realm of resistors for detecting shutdown currents or providing feedback to the circuit. A look at page 8 of the schematic shows just how complicated this circuit is and that you are probably saving yourself a good deal of trouble by using this instead of the individual components.

An added bonus for this new part is the dimmer control, with analog ratios of up to 10:1. That means that in our theoretical DC powered home of tomorrow (eat your heart out, Disney World!), we could wire in a simple dimmer with minimal cost, using an oscillator, a PWM generator, and a potentiometer built into a wall switch (and peripherals).  The dimmer control would also allow us to bring down the output current (via PWM_OUT) of the chip in order to save power.

The efficiency of this part can reach 94% in an inductive boost mode. Assuming there are no restrictions on some EMI emmitance issues and size of the parts, this could be a very good option for an LED lighting fixture in a home (with even simpler implementations also possible). Maybe one day we’ll see some wall fixtures with similar parts in them.

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Analog Electronics Work

Modesty comes in bulk doses

I am not an analog engineer yet. But I’m learning how to be.

One of the things I love about my company is that they really allow for professional development. I will have the opportunity to go back to school and we have conferences on new technologies. Last week I was introduced to the another great opportunity, a meeting with the senior engineers of the company to just talk shop and bounce around ideas. Today we had another of our weekly meetings with each other and this time we had an outside vendor come in and present new product offerings. Here’s some of the things I learned:

  1. Analog engineers find favorite parts and stick to them
    • Say you’re a salesman. Do you think you’d be in a meeting and someone there would start gushing about the product you sold 10 years ago? How great it was? OK, say you’re a doctor. Do you hear other doctors talking about the great medicines and techniques that were used 10 years ago? No? Well, we do in analog engineering. Either by habit or price or whatever drives a man or woman to talk affectionately about an often-used piece of silicon, it’s kind of weird to hear it. Doubly so when you’re in a presentation for all the NEW stuff that is coming out and you expect the focus to be on that. To be fair, sometimes chip makers get it right one time and then can’t replicate it for a while. But that’s another blog post.
  2. The same point goes for books
    • I guess this point doesn’t really hold up when comparing analog designers to other professions. I’m sure doctors still read Grey’s Anatomy, Salesmen read Dale Carnegie and Priests still read the Bible. But there are some bibles in analog design too. In fact, that was the first meeting I mentioned above. We sat around talking about our favorite books. As someone who has just about no clue about everything, I’ve been grabbing at any knowledge I can get my hands on. I love books!
  3. If you used to work at a company and then come back as a vendor, watch out!
    • Yikes. I’ve seen some pretty rough treatment of vendors before, much worse than today actually (Semiconductor vendors REALLY get the shaft, that’s all I’ll say). But today I witnessed a vendor get hit from all sides. To be fair, I feel that a good deal of the treatment was because he used to work here and then became a vendor. This meant he had personal relationships with a lot of the engineers he was fielding questions from, but he still got some doozies. Makes me think twice about jumping into a field app position anytime soon (besides my cluelessness about it).
  4. There is actually some symbiosis between customers and vendors.
    • As I mention in point 3, I’ve seen some struggle between vendors and users. But today I saw some genuine attempts at bringing the needs of the customer back to the vendor, which gives me a warm professional fuzzy feeling. Plus I’ve heard they even deliver on some of their promises, another reason I’m glad I’m in this new sector (basically you had to be THE biggest player in the semiconductor market to really influence any change).
    • Another great thing is that I found out that some vendors offer free training to new guys like me. That is great because my job requires a little knowledge about a lot of things and then the ability to quickly acquire the remainder of any knowledge. Example: I am told a product isn’t working and it MIGHT be this or that part. Go. (That’s the point I start to scramble).
  5. Converse to the above point, analog engineers love asking for the moon.
    • Well, nothing is perfect, right? And in my experience, analog designers will ask for exactly what they want, even if it might never be possible. But if you don’t ask, you’ll never know, right? It reminds me of the phrase I use when I don’t get my way:
      • “All I want is everything I want right when I want it. Is that too much to ask?”
  6. I’ve mentioned it before, but I have a ton to learn
    • I wrote down no less than 6 things from that meeting that I had no clue what they were. That’s pretty crazy. I had a very general feeling about what they might be about (I actually found out some of them have applications in renewable energy), but I still have at least a good week of reading ahead of me (on top of my usual workload) to figure out what some of these things meant. When I came into this job thinking I’d be learning, I sure had it right.

So to reuse my blog headline, modesty does come in bulk doses when you’re an analog engineer, especially when you hang out with veterans. It’s kind of refreshing though, knowing that I have so much I can potentiall learn. I know it won’t get boring and I know the industry doesn’t plan on slowing down any time soon either. Bring it on.

Categories
Analog Electronics Renewable Energy

Can DC power an entire home?

AC power vs. DC power: Both are necessary in our everyday lives and switching between the two causes a great deal of strife in electronics. Why do we need both?

As some of you may or may not know, there was a long standing battle between the two types of power raging back in the 1880s between two giants. The proponents of this war knew that whoever won would determine the future of the power distribution in the United States and possibly the world. In the first corner was Thomas Edison and his company that would eventually become General Electric; Edison wanted the world to run on DC. In the other corner was Westinghouse Corporation, funded by George Westinghouse and led (intellectually) by Nikola Tesla. Westinghouse represented AC power and would be the eventual winner. You can read more about the battle HERE, but I thought it would be interesting to point out that this battle eventually became a political one. Edison even started fighting dirty, secretly funding the invention and use of the first electric chair powered by AC, in order to give some bad press.

AC of course won out over DC as the power distribution of choice, mainly because of the ability to have large generators in a central location and then transmit the power efficiently over power lines to homes and businesses. DC would have required local generators on every street or even every home, which was not possible nor economically viable at the time.

Hang on a second though…a DC generator on every home…sounds familiar…where have I heard about something like this before? Oh right, solar power. However, even more interesting than the fact that solar power produces DC power output is that any kind of storage will have to be in DC. So THAT means if you have any kind of renewable energy resource on your premises (wind, geothermal, any kind of generator which will have an AC output) and it’s not continually supplying power to your home, you will likely need to store it somewhere (assuming you are not selling power back to the power company, which is the case in some areas still and a must in the remote areas). Further, barring any possibility of storing AC power (a huge inductor?), you will need to store that power in DC. So let’s look at a theoretical wind turbine on a theoretical property:

The wind blows –> wind turbine spins –> motor in turbine creates AC power –> AC converted to DC –> DC stored in a battery –> DC converted back to AC when needed –> AC powers devices in a home –> (possibly) AC converted back to DC for use in consumer devices

That’s a lot of steps! Not only are there a multitude of steps to convert wind into air conditioning (heh, the electrical way…the natural way is opening the window), there are lots of places that you will be losing energy to inefficiencies. These occur in the power generation (motors have friction), the storage in the batteries (heat and losses due to chemical impurities in the wet cells), the AC to DC conversion and the DC to AC conversion (both processes lose energy to heat in the electronics). All told, it’s not hard to see why this is not the preferred method of powering ones’ home.

So now the real question: Can we take out some of these steps?

Other articles on this site will deal with improving efficiencies of each of these steps, but the simplest method for improving overall efficiency would be to remove one or more of those steps. The way I see it, one of these ways would be to convert a power scheme in a house. Let’s look at all the ways a DC power system in a house could be beneficial or detrimental to ones’ living situation:

Concerns about DC wall power

  1. Many devices have different voltages
    • This would be a definite issue. Have you ever had to power a guitar pedal board? Random question perhaps, but if you saw what the power strip looks like, you’d catch my drift. Every one of those little electronic devices is too small for a transformer, so they all have AC-DC converters which can power the device with a different required voltage. Now take this idea and expand it to all the doo-dads in your house. I would be willing to guess that there are at LEAST 5 different required DC voltages for all of the normal devices in a home.
  2. Converting devices
    • Conversions would be required from DC->DC instead of AC->DC. A possible solution would be to set up the wall sockets to have selectable DC output (perhaps the home runs on 100V DC and each socket can convert this down to 24V, 12V, 5V, 3V).
  3. Selling power back to the power supply company
    • One of the most popular notions in renewable energy today is the idea of selling your excess power back to the power company, hopefully at a decent rate. Then when your device is not outputting power, you simply switch to grid power and start buying it from the power company. This is great because it does not require battery systems. And while this exercise excludes that option (for people living in the middle of nowhere or with unaccommodating power companies), it would be nice to sell any excess power back to make a small profit.
  4. Economies of Scale
    • This is possibly one of the biggest problems that an all DC power system would face: No one does it yet! All parts would have to be custom made and you couldn’t just call an electrician to come out and fix your stuff.
    • This also means that you would have a tough time buying consumer goods. Nearly every device has an AC plug, because that’s what everybody has! Not to mention all of the internal components for AC conversion and occasional power filtering (some devices need very clean DC power). Let’s just say you couldn’t go buy a TV and plug it in…
    • Government regulation would also limit any kind of large scale implementation of DC power sockets. It is almost guaranteed that it would require government certifications on many levels to allow manufacturing large enough quantities to bring the cost down for Mr. John Q Everyman.
  5. Conversion to AC for certain devices
    • Motors are the first kind that come to mind. This is basically how Nikola Tesla got started onto AC, proving that it is much more efficient when using AC than DC AND that these motors do not rely on voltage level (DC motors’ speed can be controlled by the voltage applied). This would mean you would either have to convert your DC back to AC to run the vacuum cleaner or you would have to make sure that your DC could supply constant DC and the whopping currents that those kinds of devices use.
  6. Step up/down transforming
    • You know those big garbage can looking things that are attached to power line poles? Those are changing the ridiculously high voltages in the power lines (done for transmission efficiency) down to something that we can use in our houses. Further, these are VERY high efficiency devices. For power in general, you really can’t beat AC-AC conversion; the system proposed here would have to use transistors (note: not transformers) which will have some amount of heat loss associated with them. So even though we wouldn’t be using the AC power from the power company, we would be losing a critical tool in the electrician/electrical engineers’ arsenal, the transformer.
  7. Leakage currents and phantom power consumption
    • No transistor is perfect, they all let just a little bit of current through. The more components in a system or the higher voltage you run at, the more leakage you will tend to have (Ever wonder why electronic devices run out of batteries eventually, even if you don’t use them for a long time?). This would apply to any DC system too and when you don’t have the lights on or anything running, there’s still a chance that the power devices are leaking. This will cut into overall efficiency.

Benefits of using DC instead of AC:

  1. Higher efficiencies off of battery power
    • This point was discussed above, but is THE main point of the article and for going to all this trouble. The less you need to convert between AC and DC, the less energy will go to waste. And if you do need an AC power source, the inverter could be much smaller, in order to handle smaller loads or in order to sell power back to the power company (once the battery is fully charged)
  2. LED Lighting
    • Currently any LED fixture installed in homes requires an AC-DC converter. Using a DC wiring system throughout a home would allow easy installation of LED fixtures and elements (the LEDs themselves)
  3. No 60 Hz hum
    • I’m sure most of you know what this sounds like from a faulty light switch, an older device with poor power supplies or even by sticking a fork in the wall. The native frequency of power coming out of the wall is 60Hz in the US, but varies by region. Either way, this is something that I’ve had to deal with at my job and that all electronics designs have to deal with. With an all DC system there would be other issues such as power filtering and voltage stability… no hum though!
  4. Shrinking power supplies
    • As devices continue to get smaller, the power supplies are reaching a lower limit. 1.8V is currently the lower end of DC supplies for microchips. This allows for less power consumption, as is governed by the formula P = V² * f * C (where P = power, V = voltage, F = frequency and C = capacitance). Have you ever noticed how they stopped increasing the frequency of microchips past a certain point (~3.5 GHz)? Yeah, it was because they started getting so hot you could fry eggs on the processors. Plus mobile processors became much more prevalent. As more and more devices go towards these lower voltages, there will be less need for conversion (or alternately, more need for AC-DC converters if wall power remains as AC).

So the final question comes back to that posed by the giants of the 19th century: AC or DC power? Well, really the answer will be both, as history has shown. Perhaps over time we’ll see a shift back towards DC power as devices continue to shrink and manufacturers don’t want to include bulky transformers or as people hopefully begin producing their own power at home; but one thing that is for certain is this battle will continue raging for a long time and hopefully we’ll help renewable energy find it’s place.

I welcome any and all comments on this idea and if you know of something being developed similarly, please let me know!

“If I have been able to see further than others, it is because I have stood on the shoulders of giants.” ~Sir Isaac Newton