I love StumbleUpon. If you don't know, it's a site that gives you random sites to visit at the click of a button. It's been around for a while now and it will ruin your afternoon or evening if you're not careful. It's also sent more than one visitor to this site before and hopefully exposed them to some analog engineering topics.

Anyway, I'm also a user of SU and have noticed a trend on the "Electrical Eng" side of things:

It's amazing. I love Tesla as much as the next nerd out there, but never have I seen such a recurring instance of hero worship. I suppose this many years on, the man deserves it.

So if you have a few minutes or hours to spare, click on over to StumbleUpon, check out some (ok, many) sites about Tesla and kill that productivity of yours!

We all have to start somewhere.

I've been thinking about my posts as of late. Moreso, how I can offer something of substance to readers. At least substance that is usable on a daily basis. What do EEs want to read when they get to this site?

I came up with part reviews. I started something similar at my other project, Electricio.us. Spec sheet analysis is a critical skill for any analog engineer. It's also is time consuming and hard to keep up with. So why not have a few choice parts highlighted on here? I don't plan on reviewing the newest and hottest parts...but maybe the most useful. So let's start with the LM741.

A 741? These are parts I joke about, not parts I use on an everyday basis. But like I said, we all have to start somewhere. I'm sure many of us started using this part in electronics labs and at home in hobby projects. It's the quintessential beginner op amp and it was one of the first ever designed.

LM741 datasheet from National Semiconductor

Pros:

• Cheap -- Being made by multiple vendors (necessarily called the LM741 but probably containing the number 741 somewhere in the title) really can help with cost.
• Standard pinout -- Sometimes even more valuable than having something cheap in the first place, being able to find a drop-in replacement can be a godsend when in a bind. This has been doubly true with the economic downturn. Sure, the part being out for 42 years doesn't hurt either. People managed to figure out it's pretty popular since it first arrived on the scene and duplicated this trailblazing part's pin assignments.
• Nulling circuit -- As we'll see in the "cons" about this part, the offset voltage is horrible, but the tuneability of the part is a nice feature if you have to use this part. The "offset null" pins give you access to the 1K emitter resistor circuit, basically allowing you to drive the input voltage on one side of the op amp higher by giving a different resistance for the bias current on the input stage. This effectively raises the voltage on one side of the input or the other (inverting or non-inverting). Pretty neat stuff!
• Bandwidth -- For an old part, the bandwidth on the 741 is 1.5 MHz. This is set by the internal capacitor, which acts as a pole inside the circuit and limits how fast the circuit can respond. This is extra interesting because the 741 was the first part to ever do this inside of the IC itself; previously you had to set the compensation capacitor externally. At 1.5 MHz, this old geezer of a part can still get up and move like a jackrabbit.

Cons:

• Offset voltage -- As you can see above, the nulling circuit is necessary because the offset voltages can get pretty extreme on the inputs of this op amp. "So what?" you say. Well, this causes issues when any kind of precision is required. If you put in a 1 volt signal into an LM741 that is set up in a buffer configuration, the 5 or so mV of offset voltage between the inputs will get passed directly to the output! That's .5% of your signal right off the bat! And if there is any gain in the circuit (i.e. it being set up in an inverting or non-inverting configuration), then your offset gets multiplied by whichever gain you apply to the circuit! That means for a gain of 10, your 1V input signal now has an output offset of 50 mV! Say goodbye to DC accuracy!
• Offset voltage drift --Even if you decide to "dial in" an offset null resistance on the proper pins, this is only accurate at the temperature you were at while correcting the offset. For every degree change, there is another 15 uV of voltage offset.
• Bias current -- We all know that in an ideal model of an op amp, you assume there is no current flowing into the inputs terminals. Well, that's never really the case, and having any current flowing into the terminals can cause DC offsets once that current flows through resistors (such as in a non-inverting amplifier configuration). The standard bias current spec'd on this part is .1 to 1 uA. That's nothing to write home about, especially if you care about DC accuracy. The downer on this poor spec is that there isn't an internal "knob" to help with the bias current; you just have to deal with it and try to design around it.
• PSRR -- Though it's not the worst I've ever seen, the PSRR on this part isn't great either. At a typical value of 77 dB (use 80 for easy math) that means that any noise appearing on the power rails will show up 10^-(80/4) times on the output. So if you see a 1V transient on a 15V supply rail (gah! huge!), then you will have a 10 mV spike on the output. This can cause some serious noise problems down the line and most op amps I've been looking at these days have been well north of 100 dB PSRR.

This part is old, no way to overlook that. But it is still relevant part and is the basis for many parts that exist today. That's pretty impressive some 40 years later. The downsides show the part's age but are a symptom of the technology and the time this part was developed. The transistors are BJT, compared to the MOSFET based parts of today; many of the specs are guaranteed to be worse on this fact alone (though not the speed nor the power handling ability).

If you have a simple need for an op amp and you know how to properly account for all the shortcomings in this op amp, it's a fine choice. Like I said above, it's low cost, easy to use and plentiful in supply. And if history has shown anything, it's that this part is not going away anytime soon.

So this was my first part review. I think in the future instead of running down the list of a lot of the specs like I did here, I would focus instead on one or two of the spectacular properties of a chip or the extremely underwhelming properties of a chip. Comparing all the middle of the road specs is a waste of everyone's time. I wanted to make sure I covered a few things here as a baseline for future reviews though. I'd also like to step outside the bread and butter parts of an analog electrical engineer's part drawer (the op amp) and review other types of components.

If you have any you would like to see reviewed in the future or have any thoughts about this review, be sure to leave a note in the comments.

Thanks to 畢業了吧 for the photo

The number in the parentheses are the number of positions listed online. It's fair to assume some significant number of those are repeats (Indeed.com is a scraper, not some manual entry site), but we can assume that all the cities listed have a proportionate number of repeat listings. It's also interesting-- but not surprising--to note that certain areas are dense enough with jobs and location (i.e. silicon valley) that three of those cities (3, 5, 9) only show up as one tag.

Now, this isn't to say these are the best jobs or the easiest to fill nor does it even point out how varied the positions can be! For example, an embedded developer and an analog system engineer might all be under the title "electrical engineer". If you have experience working on electronics on an oil rig you're much more likely to get a job in Houston than Fort Meade, regardless of how many jobs are available in either location. But these numbers do  point out where there is a considerable enough chunk of industry to have this many job listings.

So I ask you to respond in the shiny new comments section: are these really the only areas employers are hiring these days? Is there a significant long tail that I'm not seeing on Indeed? (i.e. 30 more cities with 250 listings each?) Are there any obviously booming spots that are left off the map? What about outside the good ol' U S of A? I know there are a couple of readers, writers and witty commenters from outside my home country. Looking forward to your responses!

I was reading about the latest WordPress 3.0 release, yet another step forward in open source software. I was eager to try it, so I updated last night. But the more interesting thing in the midst of my reading was a program also by the folks that make WordPress; more specifically, I was reading a sarcastic essay written by Matt Mullenweg, creator of WordPress. He was writing about how comment systems were in serious need of an update and was pushing for the comment system implemented in IntenseDebate. So I gave it a shot, and that's what's running the comments now.

To be honest, I'm just playing catch up; but we're also reaping the benefits of a more mature comment system (the article was from Aug '09). I like it so far! Here's how I think people on this site can take advantage:

• Reply directly to comments made by others -- No more calling out names, now it's a hierarchical format that shows your reply directly below theirs.
• Login is easier -- IntenseDebate let me create a Facebook app; not that I wanted to for personal gain, but now you can use Facebook to login to the comments here if you like. I won't take your info, I really don't want it, I promise. You can also login with Twitter, IntenseDebate, WordPress.com or it will just pull your photo in if you happen to use Gravatar (another Automattic creation, the same people that do WP).
• Subscribe to comments -- I usually "set it and forget it" when it comes to commenting on sites. Once I've dropped off my two cents, I usually don't care to stick around and refresh or I completely forget I commented somewhere. The comments subscription is easy and won't overwhelm your inbox. Plus you can reply back to any replies you get through email.
• Voting -- I don't want this site to be a popularity contest, but sometimes you see a comment you really like. Now there's a up/down arrow next to comments you think are really good so they'll rise to the top. Similar to a reddit or more relevant ChipHacker. I like the "democratic" view of commenting--just because you're the most recent doesn't mean you should show up first. Even if you're not planning on commenting, take a minute to click on comments you agree with.
• CommentLuv -- This is a plugin that will pull your latest blog post title into your post automatically. It's a simple way to show what you've been writing about even if you don't want to write "PLEASE LISTEN TO ME AND VISIT MY SITE" in every post. I doubt that anyone on the internet ever does that kind of thing though. With this new plugin, it's no big deal.
• Sharing -- I really don't think many people are submitting my posts to social media sites, but this is also integrated as a plugin (previously it was a plugin at the bottom of the post, not in the comments). If you feel the urge, I encourage it! (no pity submissions, please)

The whole point of Matt's article was building community. While I don't expect people to visit a site that I named after myself everyday, I hope that this new tool will help others interact when they see an interesting tidbit on here. I mean, people still read Joel's thoughts on software, and he doesn't even have comments! See? I'm one step up already!

Hope to hear from you in the comments, especially if you have other ideas for better interaction. Let us know if you like the new system!

I recently had the opportunity to ask some questions to Mike Demler, electronics analyst and writer at The World Is Analog. He has many years of industry experience, culminating by recently joining DIGDIA, a strategic consulting service that helps with market analysis and business planning. Let's see what he had to say:

Chris Gammell: Can you please explain your background?

Mike Demler: Explaining it may not be that easy, but I’ll give it a try.

I grew up in the city of Buffalo at the peak of the U.S. space program, and had an early interest in science. My parents nurtured that a lot, and my Dad always had some TV parts around from his part-time repair business. Those were the influences on my decision to study electronics in high school, and then as an EE student at the University of Buffalo.

In the summer after my junior year, I vividly remember reading the book “Analog Integrated Circuit Design” by Alan Grebene. It’s probably more accurate to say I tried to read it, as I know I didn’t comprehend it all so I kept borrowing it from our public library. I very much wish that I had a copy today. I was fascinated by the combination of electronics and physics involved in actually being able to create something in silicon, and that’s when I decided what I wanted to do… I wanted to design integrated circuits.

It wasn’t easy, as UB was about as far as you could get from silicon valley both geographically and academically, but through lots of luck, some independent study, the help of our department chairman and being in the right place at the right time… I got my first job as a Product Engineer for Texas Instruments in Lubbock, TX. That was my launching pad. Someone once told me that ‘TI’ stood for Training Institute, and it certainly was for me. I completed an MSEE at SMU after moving to Dallas, then went back to NY and the GE R&D Labs. We developed some very advanced (for the time) analog technology there, and my TI experience prompted me to move on to GE-Datel where I commercialized the semiconductor process and led development of a new ADC product line. After GE once again exited semiconductors, I took on a similar role starting the semiconductor product line at Unitrode-Micro Networks. I was working there when I wrote the book “High-Speed Analog-to-Digital Conversion”.

Starting up new product lines led me from engineering to sales, marketing and business development. It was during the dot-com startup/IPO boom, and I moved into EDA at that point. I worked for small pre-IPO companies like Meta-Software, then did a startup in Antrim Design Systems that moved me to California. I have also worked for Cadence and Synopsys, and completed an MBA a few years ago. Now I work as an industry analyst, focusing on new disruptive technologies in mobile wireless.

CG: How does your experience in the EDA industry and the semiconductor industry affect your work now?

MD: I’d say that it gives me a unique perspective on the role of those components in the broader electronics ecosystems, such as the wireless industry. When I was in EDA I worked for a while on vertical market strategies. Though they wish it was otherwise, EDA is a small component in a much bigger picture, and most design tools are not easily differentiated by end-market application. Now I get to have the higher-level view of where the customers of the customers are going, and I try to provide insight on how it all fits together both top-down and bottom-up.

CG: What kind of companies do you interact with as an analyst?

MD: I mostly focus on the wireless industry, and currently I am working on an analysis of the Android ecosystem. The variety of companies is almost endless, especially since I try to provide that unique point-of-view from chips to consumer electronics, to services and applications, networks, etc. There are big companies like Cisco, Intel, Qualcomm, Motorola, HTC, LG, Verizon, AT&T…. the list goes on… to numerous small companies, some that are behind the scenes that you are unlikely to hear of unless you are in the industry.

CG: How soon before a product comes out do you get to hear about it?

MD: I don’t get that much special advanced notice of future products, but I think that one of the values I provide is that because of all the sources of information I have, I can tell where things are going ahead of time. Companies sometimes provide advanced information under NDA, that could be from one quarter to a year before you see it in a product. You can also learn what sources of “unofficial” information to trust. The most pointless advanced information I get is when a PR rep send me an unsolicited press release “under embargo” before a major trade show or conference. I haven’t seen one of those yet that was a big deal.

CG: What kind of impact can your work have on the industry? Are there consequences to being right or wrong about your industry predictions?

MD: I wouldn’t presume that I influence the industry in general, but I can have an impact on individual companies that use my research and insight. I stay away from far out predictions, and you won’t see any press releases from me that say “DIGDIA forecasts X million users of Y in 2014”, that you see every day from other analyst firms. Those forecasts are vaporware designed to get repeated on the internet. If I am right about trends and I point out important factors in one of my strategic analyses it improves my credibility. If I am wrong, then not.

CG: Your blog is called "The World is Analog". How do you view the role of analog in devices today and what role do you think they'll have tomorrow?

MD: My point of view in “The World is Analog “ goes back to my answer to your first question. At the risk of being seen as a technology bigot, everything is in reality analog. That is not to say that I don’t appreciate the aspects of design that are digital, or computer science in general, etc. but nothing works unless you build it, and all devices are governed by the (analog) laws of physics. Digital is just an abstraction of the underlying analog behavior. Those analog physical aspects of a design are becoming increasingly difficult to ignore even in digital design; factors such as dynamic voltage variation, power management, statistical process variation, etc. On the other hand, analog circuit functions are enhanced by digital controls, and that inter-dependence will continue to grow going forward.

CG: What do you see as the future for electronics? What kind of devices will people own in 5, 10, 20 years from now?

MD: Electronics will continue to grow and enhance so many aspects of life. The 5-year horizon is what I am focusing on, which will be dominated by ubiquitous wireless connectivity to the internet. This is going well beyond smartphones--to other areas of consumer electronics, energy management, home security, and health and medicine. Those describe some of the broad categories of devices people will “own”. I also see bioelectronics, I suppose you can call it call it bionics, as one of the big growth areas. Today we have devices like pacemakers that help to control heart function, but imagine how nano-electronics and smart wireless sensors can be used to monitor and control other body functions. Transportation is another area where we are just beginning to see what embedded electronics can do. I think the cars that can automatically parallel park are amazing, but people seem to take an advance like that for granted. We will see more “connected vehicles”, with real time 4G wireless connections for information, traffic control and numerous other functions.

CG: It seems that you have transitioned to the business side of things from your early days in engineering. How do you interact now with managers, engineers, marketers and others in the electronics world?

MD: Well, I’ve been in all of those roles, so hopefully it helps me to better understand where people are coming from when I interact with them.

CG: Where do you view the industry itself going? Will all electronics end up in Asia? Will things ever move back towards the US?

MD: There is no “moving back”. It's like Thomas Friedman wrote in “The World is Flat”; manufacturing will always go to the lowest cost location. Everyone needs to take a global view in every industry today.

My greatest concern is education. By growing up during the Apollo space program, I benefited from a societal focus on developing advanced technology. The U.S. needs to work harder to develop more scientists and engineers amongst our own citizens. I hope that environmental concerns might stimulate the current generation of students in a similar way, but I can’t say I’m optimistic at this point.

CG: Is there a maximum growth potential for the market? Won't people stop needing devices? What happens then?

MD: No, the market for electronics devices will grow many times over where it is today. I don’t limit that statement to mean only consumer electronics devices. We can only carry or interact with so many. But the connected world is only beginning to be developed; for in-body, in-home, in-vehicle, in the environment.. the list is endless.

Many thanks to Mike for taking the time to explain his view on the (apparently analog) world. As you may have noticed from other posts on here about talking to various professions, I'm very curious about the electronics ecosystem.  I find it fascinating how different job functions look at similar situations, especially when those people are selling or buying products from one another. The customer in one scenario often turns around and becomes a supplier to someone else. The interdependencies are intriguing. You may also notice that I have been targeting people that write for their own sites or for their companies sites. While I intend to focus on the less well-known positions eventually, why not show off the great content they have already written on outside sites? Be sure to click through to their relevant posts from the links above.

Two questions:

1. Do you (the reader) enjoy seeing these perspectives? I know I always appreciate the freshness that other perspectives add to this site, but am not sure that others feel the same.
2. Do you have any questions for Mike specifically? These can be questions about the future of the industry (though I thought he gave some good explanations on the direction) or his past experiences or really anything!

Please leave your notes or questions in the comments area!