I’ve looked at a lot of resumes for electronics positions, so I thought I’d share some of my opinions on what should or shouldn’t be on there. Nothing formatting specific, so much as how to get across your interest and passion in electronics. I used examples that are resumes meant for engineering internships, but a lot of the info can be generalized to anyone. Hope you enjoy the video!
Here are those two resumes, if you’re interested: The bad (1st) version and the better (2nd) version.
Aside from the 555 contest I mentioned in my last post, my February was spent building the workbench I drew in Google Sketchup. It was built partially for The Amp Hour, partially for circuits I plan on building and showing off on here and partially for my new business, Analog Life, LLC.
So for today’s show and tell, I’ll premier the first video ever with me in it on YouTube:
I also had a couple snapshots of the bench in progress:
So my bench is done now and I’m off to put it to good use!
So it’s quite apparent I haven’t been around posting too much. The date on the last post makes that pretty obvious. I have been doing some fun and exciting things though!
First off is The Amp Hour, a new electronics podcast/radio show. We just completed our 8th episode yesterday and it seems to be going well! We were very lucky to have much of Dave Jones’ wonderful community at EEVblog make the jump over and listen to us. It’s nice to have a strong base of listeners to start with and we appreciate everyone of them (I appreciate you doubly if you happen to read here as well!).
Next, I’ve been reworking my electronics lab at home, building up my gear holdings and working on some new projects. It’s been really fun, if not time consuming. All of the time that used to go towards bugging you with blog updates seems to be eaten by that activity. I know there will be lulls in the future, so I’ll try to blast out some ideas I’ve had rattling in my head when that happens. I’m really interested in a topic we discussed on The Amp Hour known as “The Creative Economy”. Basically the idea that so much equipment has become such a commodity that the only true value to add to products and services will now be based on how creative you are. It’s already started and it will only become more apparent.
And lastly, on the same note as above, I’ll be attending the Open Hardware Summit coming up in NYC. It’s right before the Maker Faire (which I won’t be able to attend unfortunately) and should give me and everyone reading this even better insight into the thing fueling much of the creative economy: open source hardware. The few days prior to OHS, I’ll be at ESC Boston doing some freelance work for EEtimes (on their EELife blog section). I’m looking forward to that as well. It was a direct result of going to the ESC in Chicago, which I’ve written about on here a few times.
So that’s it for now. Talking, doing and writing. That is my life. And I enjoy it. And I hope to share more of it with you soon, so please hang on.
I’ve asked communities I’m a part of where all the electronics sites are. The truth is there are some out there, and the popular ones are there for a reason. They produce a lot of great content and highlight engineers and hobbyists who really contribute a lot to their respective communities. But why aren’t there more? Are electronics just innately uninteresting? I don’t think so–obviously–or else I’d have a bit of a conflict of interests. So what is it that prevents more people from publishing sites about electronics?
Of the sites that are out there about electronics, some really stand out in my mind. The Electronics Engineering Video (EEV) Blog, Chiphacker, Discovercircuits.com and so many more. They provide great services to people, which keeps them coming back. But what about these sites really draws people in? I’ve pondered this question in terms of what might make more people want to read my site. Here’s what I’ve come up with:
While I don’t think the hardware sites have quite reached the critical mass that software development sites have reached, I’m not worried. The hobbyist movement continues to grow and I believe the general population has been re-warming to the idea of working on electronics (at least some part of the population, that is). Given the slow uptake of the hardware community with new media, it’s not all that surprising that we haven’t seen as many sites as we might have expected. However, I think we’ll be seeing more soon. What do you think? Have I missed any big categories of websites? Or are hardware engineers and their respective interests always doomed to remain in the shadows?
Even though I’ve stated that I’m not as interested in sustainability as I used to be, it doesn’t mean I don’t think about it. I have been thinking about it in conjunction with investing and my own work in the electronic industry.
Growth is a very important component to the electronics business. It’s priced into many stocks and it drives much of the electronics food chain. Moore’s law has helped for a long time too. Shrinking the geometry of silicon every 18 months really required manufacturers to update their equipment often. This then drives the equipment manufacturers to advance technology to make the new fabrication possible. The analog engineers (ok, digital too) out there utilize the new chips and make requests for the next generation. The ripple effect continues all the way down the line, requiring input from the manfacturers and returning revenue to the shareholders of said manufacturers. Like I said, this growth is an assumption and is priced into how people invest in companies involved in electronics manufacturing.
There’s no denying that electronics are a dirty business. Not oil-gushing-from-a-hole-in-the-ocean dirty, but still, not exactly the most environmentally friendly situation either. The chemicals used in semiconductor manufacturing are not known for their safety nor their easy disposal; I’ve only had training on how bad they can mess people up but it goes beyond that; there are entire departments in semiconductor manufacturing facilities devoted to containing and disposing of the chemicals. Outside of the semiconductor world manufacturers have had to drastically reduce the amount of lead in products (in the solder and otherwise) but there are still elements of boards and parts that are not good for the environment. And given both the amount of turnover in the products that people consume year to year and the fact that very few products are designed for long term use, almost all electronics are bound for a landfill within a 10 year time frame (unless recycled). All of this adds up to a nasty picture for the planet.
A business built on growth and components that are not biodegradable nor regulated in their disposal. Is this model sustainable? Can manufacturers continue making products that are not safe for disposal and yet expect people to continuously update their personal electronic portfolio at home? Can manufacturers continue to crank out new devices ad nauseum and not be held responsible for the impact they make?
I do not believe the long term growth of electronics will plateau. While this may be good for my own career, part of me is very conflicted by the idea that my own success could be tied to the fact that we will have to consume more and more over time. Growth will always be driven by the next “must have device”, updating of previous generation devices and bringing electronics to a greater percentage of the population. But how can we rectify the needs (or perceived needs as it may be) with the very real issues and impacts associated with modern electronics? The material and energy inputs required and the waste from technology churn all make for hundreds of miles worth of disposed and forgotten cellphones and CRT monitors which took large amounts of the earth’s resources to make.
So assuming that growth of the electronics industry will continue unabated for various reasons, I think the question is better asked: Is a sustainable world possible with the electronics industry as we know it today?
I don’t usually say it on this site, but I have no clue about the answer to this question. Do you? Is it possible for there to be a healthy electronics industry when taking the planet into account? How does this affect the business model and should the people that manufacture products be responsible for what happens to the at the end of the products’ lifetime? Please let us know in the comments.
OK, so I know that just about everyone else on the internet is doing the same today (I’ve read them), but I thought I would also say what I’m thankful for.
So thanks to all those listed and all those I forgot. Have a great Thanksgiving and enjoy the madness of the holiday season that is now upon us!
How does an op amp work? How do I use an op amp
These are questions that I have asked at two periods in my life. The first time was in my introductory circuits class and around that time I really didn’t care (beer was a priority). The second time was when I dove headfirst back into analog electronics for my new job and had to re-teach myself a lot of things. I really appreciate the opportunity I had to re-learn everything because the second time around, I think I got it right.
OK, so let’s start simple. What is an op amp? Whoa, loaded question. For our purposes here (and just for now), let’s say it’s just a symbol.
To keep things basic, the A & B points are the input, the C point is the output.This symbol is an IDEAL op-amp, meaning it is impossible to construct one and really the expectations for the op amp are unrealistic. But this is the internet and we can do what we want on the internet, so we’ll just use the IDEAL op-amp for now.
OK, so now you know what the symbol is, but what does it mean? Well, the idea is you put two electrical signals into the inputs then the output changes accordingly. It takes the difference between the inputs and amplifies it, hence operational amplifier, or op amp. You may have noticed that input A has a minus symbol and input B has a plus symbol. So let’s say that the input to the minus, or INVERTING, input is 1 (for simplicity’s sake…this site is about analog so that value could be ANYWHERE from 0 to 1 or higher! Just thought I’d mention that). The input to the plus, or NON-INVERTING, input is 0. Now the op-amp is in an unbalanced state. The device is designed so that when this happens, the output goes as negative as it can. For the ideal case, we say this is negative infinity, but that’s not really possible. More on that later.
Conversely, in figure 3, if we put a one on the non-inverting and a zero on the inverting input, the op amp output would go high, infinity for our purposes here. The important thing to know is this:
The op-amp always “wants” both inputs (inverting and non-inverting) to be the same value. If they are not, the same value, the op amp output will go positive or negative, depending on which input is higher than the other.
(Throughout this article I will continue to anthropomorphize op amps…best to get used to it now)
Alright, so how do we use this in circuits? If we wanted to find out if two signals were different, we could tie the signals to the inputs of the op amp, but then the output would go to infinity. This would not do us any good. The answer to this and many other questions in the universe is feedback. We are going to take the output and tie it back to the inverting input. Now the circuit looks like this:
First, we assume that the circuit has all points start at zero (point A being the most important). Next, we put a value of 1 (like the picture in figure 2) at the “B” non-inverting input. “WHOA,” says the op amp, “THIS AIN’T RIGHT!” So now the op amp puts its output to as high as it can, as fast as it can. This feeds back from the output (“C”) to the inverting input (“A”). So as the output moves closer to 1, the op amp is happier and backs off the output. When the input at A is the same as at B, the op amp is happy and stays there (but maintains the output of 1). The key here is that the op amp moves as fast as possible to get both inputs to be the same.
Why would someone use a buffer? Well that brings us to the next point about op amps, specifically ideal op amps:
Ideal op amps have infinite impedance (resistance) at their inputs. This means that no current will flow into the op amp.
A common use for a buffer is to supply current to another stage of a design, where the buffer acts as a gateway. So when the buffer “sees” a voltage at the input (“B”), it will output the voltage at “C”, but will also drive that voltage with current (as much as you want for an ideal op amp). This would be useful if you have a weak signal at the input, but want to let some other part of a circuit know about it. Perhaps you have a small sensor that is outputting a small voltage, but then you want to send the voltage over a long wire. The resistance in the wire will probably consume any current the sensor is outputting, so if you put that signal through a buffer, the buffer will supply the necessary current to get the signal to its destination (the other end of the wire).
What if the signal coming from the sensor is too small though? What if we want to make it bigger? This is when we turn the op amp into an amplifier, using resistors. One of the more common ways of doing so is using the inverting input, shown below:
Let’s go over what we know about this circuit. We know that the op amp wants both inputs to be the same. We also know that the non-inverting input is zero (because it’s connected to ground) and so the op amp will want the inverting input to be equal to zero (sometimes known as a “virtual ground”). In fact, since the op amp has feedback through the top resistor (squiggly line if you didn’t know), then the (ideal) op amp will output just about any current and voltage in order to get the inverting input to be equal to zero.
So now our situation. A dashing young engineer hooks up a voltage source to the point “IN” set to 1 volt. This creates a voltage at the inverting input. “WHOA” says the op amp, and then it begins to output a voltage to make the inverting input point equal to zero. Since the input is 1 volt the op amp decides it better do the opposite in order to make the inverting input match the non-inverting input of zero. As fast as it can (infinitely fast for an ideal op amp), it outputs -1 volt. The inputs are both zero and everything is right in the op amp’s world. What about current though? We remember that current cannot flow into the op amp at the inverting input, so any current will be flowing through both resistors. If we have 1 volt at the input and a 1 ohm resistor at the input, then we will have 1 amp of current flowing (according to Ohm’s law V=IR). So when the op amp outputs -1 volt across the top resistor, there is a -1 amp going through it (assuming it is a 1 ohm resistor). The currents cancel each other out at the inverting input and the voltage then equals zero. The place where the currents meet is sometimes called the “summing node”. This is a useful representation when dealing with currents as opposed to voltages.
For the last part of this thought exercise, let’s look at a situation where the resistors at the input and at the top of the circuit are not the same. Similarly to above, the same dashing young engineer puts 1 volt at the “In” node. The resistor is still 1 ohm, so there is 1 A of current flowing through to the summing node. The op amp once again sees this 1 volt and once again says “WHOA, I’m unhappy about this” and starts outputting the highest voltage it can. However, in this situation, the top resistor is now 4 ohms. In order to create the -1 amp that is required to cancel the 1 amp going through the input resistor, the op amp must output -4 volts (remember V=IR). We see that for an inverting op amp configuration, the ratio of the resistance of the top resistor to the bottom resistor determines the gain, or a multiplication factor from the input to the output. Also notice that the output is negative for a positive input, confirming that this is an inverting amplifier.
That’s the basics of it. Check back here for more about op amps, because there is a lot more to be said. Future posts might include other op amp configurations, design considerations and even the dreaded “REAL WORLD”, where the ideal op amp no longer exist.
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