Hackaday Prize Entry: Teaching OpAmps

TI makes some great chips, and to sell those chips, they’re more than willing to put together some awesome tutorials, examples, and online classes to get engineers up and running. This isn’t limited to $5 Launchpads; TI has a great video and lab series for their precision OpAmps. These tutorials come with an evaluation module that costs about $200. Yes, that’s two Benjamins for a few OpAmps and a PCB. Of course no engineer would ever pay this; their job would. But what about someone who wants to learn at home?

That’s where [SUF]’s project for The Hackaday Prize comes in. He’s building a replica of a $200 lab board, and even without researching the cheapest solution for each individual component, [SUF] reckons he can build this kit for about $50. Like I said, the TI board is a business purchase.

The complete lab and tutorial TI offers uses NI’s virtual lab. This, again, isn’t something a random electron hacker could afford, but anyone who wants to go through this teaching module would probably use their own tools anyway.

As far as projects to teach electronics go, [SUF] has knocked it out of the park. He’s already relying on excellent tutorials, but bringing the price down to something a little more sane and amenable to checkbooks that aren’t tied to the corporate account.


The 2015 Hackaday Prize is sponsored by:

27 thoughts on “Hackaday Prize Entry: Teaching OpAmps

  1. You don’t teach opamps by using a PRECISION opamp demo kit. You teach it with a kit made with more garden variety components. Complaining that this is expensive is not relevant.
    Plus, for such a tool, 50 is expensive. Unless you throw in a micro with reasonable ADC/DAC so that I can use it as I/O for the opamp circuits directly connected to a computer without all the expensive instruments you would need around.

    1. Hi,

      Yes the 50 bucks also two much. Believe me, it will not cost that much either, it was just my first round on the components, calculating the shipping cost into it. After picking things from my drawer, finding cheaper sources, tha actual building cost will be way bellow.

      SUF

      1. Doesn’t the use of precision opamps preclude the teaching of any of these things?

        If the goal was to present these problems wouldn’t it make more sense to use IC sockets and supply DIP op-amps with various properties to show what happens when you don’t choose the right part?

        You forgot opamps whose common mode input range does not include ground…. TL072…

        What about higher order filter circuits that don’t have opamp buffers between them?

        What about medium – low impedance filters like Twin-tee that don’t have buffers between them?

        What about noise figure?

        What about single-ended circuits? How many practical circuits are you really going to field that have a -DC supply? What is the trade off?

        What about input offset voltage in sensitive circuits?

        PSRR and power supply noise?

        1. Exactly, lower performance(and cheaper) parts are so much better for teaching: easier to see 10mV offset than 10u, easier to see a GBW of 1MHz than 100Mhz etc. Basically lower performance means lower performance tools to see the effects.

  2. Not even sure if the board is for engineers at work. I can see it for school and TI’s sales engineers. It would be strange to send your analog guy out for training basic stuff like opamp. They should already be familiar with it. These day companies hire people to expect that they already have all the training and hit the ground running. The math and theory should be in 2nd year core Electrical Engineer course, so even digital engineers would pretend to know it.

  3. The evaluation modules aren’t cheap but they’re not really intended for personal use. Your company would buy it for you or if you’re a big enough potential customer then the manufacturers will send you these kits for free. When I was doing a lot of stuff with Maxim ICs, I’d just call up my sales rep and ask for the eval kit. They’d ship me one along with a few samples. The cost of the kit was more than offset by the purchases my company made if we did pick their part. Once they knew we were a reliable customer then they’d ship out any kits for new products which they thought we might want without us needing to request it.

    1. Essentially the same model that was used through the 1990’s for the data books. You could buy them– as I recall the TI 7400 logic book was about $50 in the mid 80’s– or, if approved, get them for free through sales. The rep explained it to me, back in the day, as the company needed to assign a value, and have a true, retail price with retail channel and all, to apply as a business cost to the sales department for deduction from taxes. If the item wasn’t available that way, then the applicable deduction was much lower, maybe printing cost only.

      The sales reps had little concern about giving things away to students or pro’s, even if they knew it wasn’t likely to run to a sale directly, as you would then be looking to them for other things that you would be purchasing. They just didn’t want to be bothered with hobbiests. Some companies made money on the givaways, as the assigned values cut the net (on paper) dramatically.

      1. You’ve hit the nail on the head there, dude. Tax write-off. They don’t expect people to actually buy them, most of their customers are gonna get them for nothing, so set the price to something credible for a write-off, not competitive for customers.

  4. I appreciate the effort to reduce the price for such evaluation board, but I don’t find this project quite right for the HaD prize; replicating a hi-fi opamp evaluation board using cheaper parts kinda kills the hi-fi part of the thing, and I agree with other people reporting that the average person on this site knows the basics of opamps usage. There’s way more interesting stuff running for the Prize than this.

  5. You could put a half dozen opamps each with their own adc and a microcontroller to display it all over usb and for good measure a few resistor/capacitor/inductor ladders, yet still come in under the two hundred mark.

  6. Nobody has asked the question, “Why does TI even think we need a tutorial on op-amps more than fifty years after the first i.c. op-amps appeared; and at least 35 years since op-amp design–by fab houses and designers–was considered a VERY mature subject?”

    What’s next–a $299 “tutorial” on logic design?

    Or might this be considered a response by an extremely astute engineering entity to a serious failure on the part of our technical educational process?

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