Op Amps Without Circuit Boards




Introduction: Op Amps Without Circuit Boards

About: I'm an applied physicist by training(phd Yale 2006, BA Berkeley 1998, math and physics), and have done physics research in the federal government and product development in the private sector, starting two o...

This is another example of fabricating circuits without circuit boards or breadboards, using direct solder and wires and tweezers in 3 dimensions. I'm using the MCP6241 op amp here, and making one amp of voltage gain 10,000 and one of voltage gain 100. I use a combination of surface mount and axial resistors, and I don't specify which one you use when. Also, the instructions here are assuming you already know and care about op amps, I'll have another more basic one for beginners later. I show schematics I'm going off of directly as I go. Again, I advocate in most cases, keeping that schematic with the physical thing for future users to be able to understand. That schematic should also contain a URL back to your or my or someone else's documentation.

Step 1: Cut Off Unwanted Leads

pins 1,5 and 8. Cut them off with clippers! Smash!

Step 2: Add Feedback Resistor

I use a 1 M Ohm 0603 SMT resistor for this every time because I bought a ton of those a long time ago and have an effectively infinite number and that gives me a ton of choice for gain based on the input resistor.

Step 3: Add Input Resistor and Other Bias Resistors

As shown. That's it. If you're making a simple circuit with a simple op amp, you should never need either a breadboard or PCB. Just grab, solder and go.



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    7 Discussions

    Another approach to building a circuit is to use a breadboard:


    With breadboards you don't have to damage the chip or cut the pins. Everything just plugs in without solder. And if needed you can reconfigure the circuit in a few minutes. Also when you are done all parts can be reused in your next project.

    1 reply

    yep, solderless breadboards are the way to go for prototyping, this is all about more permanent circuits.

    We called this "spiders" when I started electronics decades ago.

    1 reply

    I like it! That term should come back hopefully.

    I agree that that is a very hard problem. Part of what I find interesting about this platform(Instructables) is that it poses a possible solution. Suppose that you could scan the inside of broken electronics "trash" with your phone and part numbers would link you to data that exist on how hackable that particular part is. If such a system were automated, even if 9/10 of the parts are unusable, over time you could get whatever you needed. Clearly that's not possible now, but I think it's research worth pursuing because the sheer quantity of electronics in landfills globally is astronomical and growing.

    Free form circuits are a lot of fun to make. What's really cool is that if you have multiple of the same IC, you can stack them on top of each other and share the same power terminals (and any other shared terminals).