Opamps are extremely useful in audio electronics. It’s very hard to implement an analog circuit without an opamp. In very early designs people have use transistors instead of Opamps. That’s because Opamps very expensive back then, but now they are almst the same price.
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Still, it’s very hard to implement voltage controlled oscillators without transistors in pure analog circuitry.
In Bread modular we don’t have analog VCOs because, it’s very hard to work with transistors as they tend changes as the temperature and humidity changes. So, we need to focus more on tuning & that’s not fun.
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Opamps can be used as multiple mode(or configurations). Here we discuss about buffer and inverting amp modes.
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There are many types of opamps which has different characteristics. In our case, we work with 0-3.3V. So, we need an opamp which can work with full voltage range (which is not true for most of the opamps).
These opamps are known as rail to rail Opamps(usually a bit more expensive than other pampas). In our case, we use MCP6002. Which is affordable & decent for audio.
If you work with 12V or 9V, you can use TL072 opamp. Which is very affordable and very high quality for audio applications.
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Be careful when sourcing OpAmps from AliExpess and local shops. Since they might be fakes and you won’t get the desired result.
So if possible try to get them from a reputable source like DigiKey, Mouser or LCSC(China).
Also there are Chinese makes of popular Opamps (which uses the same designs). They are clones but not fakes. If the manufacturer is well known, they are almost the same as the original.
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This is a very useful mode of opamp. It looks like below:
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In this mode, Vin and the same as Vout. But this has very interesting characteristics:
If you look carefully, now with buffers we can fix two problems we encountered in previous part of the course.
Before we fix them. Let’s let’s learn more about pins: