Electronics > Beginners
How woud an experienced person "know" how to build the circuit?
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Beamin:
I'm asking a subjective question. Would you start by drawing out the main parts like the op amp microphone etc then figure out how to connect them? Or would you look up a basic circuit then start modifying it? I can read circuits but I can't really build them. The most I can do is take one and change a few parts so I'm trying to best figure out if memorization is better or experimentation. As far as the values go do you just guess at them and see what works when you build it or do you use a formula like e=IR for each one then build it and see if the values are too high low? If you were making this from scratch would you use an oscilloscope or just a simple multimeter to get it working (assuming you don't use the scope as a meter because you are that good)?

I realize there isn't one answer to this but it would interesting to see if there is a right way based on what I know about members vs a lazy way or more build it see what happens then work out the math vs do all your experimentation with formulas...

When learning in school do they teach you a whole bunch of circuits or do they tech you the parts in such detail that the circuits just become an exercise of the mind vs recalling a memory?

https://youtu.be/b0A_5H801rk
ataradov:
Most of the circuits out there are combinations of a few basic building blocks that take inputs and produce outputs. Over time you learn those basic blocks, but it is fine to just look them up.

The rest is just matching outputs to the inputs.
JS:
There are many different ways, most of the time you are good to go with standard configurations or app notes in datsheets, so no need to reinvent the wheel. When picking values, usually there is a cryticall part like input resistance/impedance for the first gain stange and all around that fall off to configure gain and poles. You don't need to memorize them, but knowing they exist and what to search in google is usually good enough to start. The things you use often ends in your mind anyway and the standard values to start playing around as well, ballpark figures so you don't ensld with reardo values ir impractical circuits.

Then once in a while you need a very specific application where you nees to go with something new, could be a special topology using conventional blocks like opamps or a 555 or a wired application of a particular component like exploding them as they weren't intended to be used. In those cases you nees to be more creative, an idea hits you ans you start to work around it, simulations are sometines helpful but quite some experimentation is needed to be sure the circuit behaves as intended in every scenario. You can't memorize those, you need to know what you are doing and be creative, think, when you are getting a shower or a coffee. Experience is a big part of this, knowing circuits and analysing special circuits and application gives a lot of tools for the task.

JS

german77:
That depends, if you have already the components you figure out how to connect them. If you don't, you start with the basic circuit and modify it to your needs then search for components and make little adjustments to make it work.

In my case I often start with some components the most important and expensive ones. Then depending on the complexity I split the circuit into many basic circuits and expect an ideal input and output of the circuit. After that I adjust or add what its needed to work with the components I already have and do some quick simulations. Then I start joining those small circuits to make a big one. finally I start changing parts to make it simpler and add some circuit protection.

A good example should be the microSupply that Dave made. You start from a small and simple circuit then start adding complexity until everything works as you like.

For the values most of them are quick V=IR and transistor formulas like Ic=B Ib. Others require Logarithmic functions like the discharge time/voltage of a capacitor. Some are RLC formulas that are a little bit more complicated. And finally most datasheets have circuit examples. I often start with the circuit on the datasheet do the first two formulas by hand to get values to start with. Then start guessing comercial values for the other components until it looks good enough, it's faster than doing all the calculations with formulas.
IanB:

--- Quote ---I'm asking a subjective question. Would you start by drawing out the main parts like the op amp microphone etc then figure out how to connect them? Or would you look up a basic circuit then start modifying it? I can read circuits but I can't really build them. The most I can do is take one and change a few parts so I'm trying to best figure out if memorization is better or experimentation.
--- End quote ---

This is about the process of design.

You start out in your mind with an idea of what you want to achieve, and what steps are required to get there.

For each step, you need a functional building block that can perform that operation or function. In your mind, you will have by learning and experience a collection of possible building blocks you could use. You will pick one of them based on what is available, or by various other factors that help to limit your choice.

In this way, you build up the whole design block by block.


--- Quote ---As far as the values go do you just guess at them and see what works when you build it or do you use a formula like e=IR for each one then build it and see if the values are too high low?
--- End quote ---

This is the next part of the design process. For each building block you have chosen, there will be specific rules for how to select component values for that block (for example, how to achieve the correct biasing, or frequency response, or stability).

Experimentation, or testing, is very important. Just because a design "works" on paper, it doesn't mean it will work if you build it. You have to take that final step of building it and measuring its performance before you can be comfortable you have it right.


--- Quote ---When learning in school do they teach you a whole bunch of circuits or do they tech you the parts in such detail that the circuits just become an exercise of the mind vs recalling a memory?
--- End quote ---

Generally you will get to learn typical example circuits, and also details of how components work individually, and also the theory of how components interact with each other in large systems.

With experience you eventually learn how to find your way through complexity to quickly arrive at working solutions.
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