Electronics > Beginners
I'm spoiled by Arduino and I want to learn the things I missed out on
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fourfathom:
Others have already said this, but EE is *mostly* easy math.  There are areas where the hard math is required, but when starting out it's generally pretty simple.

Understand voltage, current, and Watts.  Learn Ohm's Law and the permutations of E, I, R, and while you're at it P.  Kirchoff's and Norton's Laws are pretty obvious -- don't be intimidated.  Figure out how to make a voltage divider, and then see how it works with source and load resistance.  This is all DC stuff, and you *need* to understand these fundamentals.  This should take you a day or two (or an hour or a week, depending on your experience.)  Algebra is the only math needed, and plain arithmetic is usually sufficient. 

Learning about AC vs DC is important, so look at RMS, peak, average relationships.

Then look at capacitors and inductors.  You can use the fancy math if you like, but I would rather see you get familiar with how they behave at a more "hands-on" level.  Look at graphs of charging and discharging, R-C time constants, simple R-C low-pass and high-pass filters, etc.  They are all related, and understanding the time-domain and frequency-domain behavior is important and extremely useful.  You don't need hard math to get a practical feeling for this, or to be able to do simple (but useful) designs.  Use a circuit simulator like LTSpice to see what happens in simple circuits.

By this time, now that you are comfortable with the fundamentals you should be ready to look at diodes, transistors, op-amps, and other active devices.  You can get into the hard math as you decide you need it.  Don't worry about it now.
rstofer:
In the first 5 minutes of the w2aew video linked above, he covers the fundamental ideas of op amps.  A couple of preliminaries:  He is using the LM358 op amp - you should have a dozen or so on hand.  He is operating it from a single supply of +10V.  That is why he has the 'rail splitter' resistors (2.2k as he points out) providing a reference voltage (virtual ground) of +5V.  That +5V goes to the + input of the op amp.

Due to op amp action, the voltage on the - input will also be 5V.  Assuming an ideal op amp, as he is, that - pin will ALWAYS be +5V.  From there is is easy to see why, with 4V applied to the input resistor, there will be 1V drop across the resistor.  Ohm's Law gives us 1V / 10k = 100 uA of current flowing away from the - input.  But, from the rules, that current is NOT coming out of the op amp pin.  No, the current comes through the 20k feedback resistor.  That same 100 uA times 20k (Ohm's Law again) provides 2V drop so the output voltage is 2V above the 5V reference or 7V.

They really are as simple as that!  No current in or out of either input and no voltage difference between the inputs as long as negative feedback is applied.  Technically, we played with Kirchhoff's Current Law at the - input but didn't call it that.  The current into the node from the 20k resistor is equal to the current out of the node through the 10k resistor.  The node is the - input pin.  No current spills out on the floor and no current comes out of the pin.

Get a breadboard and some source of 10V (or a 9V battery, change the arithmetic, the + input is now 4.5V) and follow along.  I'll bet within a couple of viewings and matching experiments, you will understand op amps and the majority of circuits you encounter.

I prefer NOT to have to use a rail splitter.  I want a real ground just because it makes the math easier.  The + input actually IS 0V, not some virtual value.  For this you need dual supplies if you don't already have a PS.  +- 15V is fairly common and right on the edge of what the LM358 can handle.  I bought a dual 15V supply from Jameco.com.  You would probably need to find it from a different supplier.  Or build one.  Earlier I mentioned 7812 and 7912 regulators, 7815 and 7915 will give you the maximum supply of +-15V.  Ordinarily, you would design for a +- 10V signal swing.  This leaves a little headroom between the signals and the supply rails.

There are modern 3V single rail op amps around but many of the projects you will find on the Internet will be using the old uA741 with dual supplies.  You can substitute the LM358 and save some money.  Those old 741s are like gold!

You really do need to breadboard the circuit and follow along with the video.  It won't take long before you have it mastered.
rstofer:

--- Quote from: fourfathom on August 28, 2019, 05:44:57 pm ---Then look at capacitors and inductors.  You can use the fancy math if you like, but I would rather see you get familiar with how they behave at a more "hands-on" level.  Look at graphs of charging and discharging, R-C time constants, simple R-C low-pass and high-pass filters, etc.  They are all related, and understanding the time-domain and frequency-domain behavior is important and extremely useful.  You don't need hard math to get a practical feeling for this, or to be able to do simple (but useful) designs.  Use a circuit simulator like LTSpice to see what happens in simple circuits.

--- End quote ---

Use an Arduino or 555 timer to generate a square wave and use it to charge and discharge an RC circuit.  Watch the exponential charge and discharge on a scope.  Set the square wave time to be about 6 times the time-constant of the RC circuit.  10k 100nf = 1 ms time constant.  Set the square wave so each half is 6 ms (so total 12 ms) and figure the frequency as around 83 Hz.  Pick a number <= 83 Hz.

If the OP is test equipment challenged and the goal is to learn electronics, the Digilent Analog Discovery 2 is the way to get started.  I'm not going to enumerate the features but suffice it to say that a LOT of electronics can be done with no other equipment.  A DMM or two might be an advantage.  A couple of AN8008 would suffice as long as they weren't to be used on mains.

I particularly like demonstrating the RC charge/discharge example using the AD2.  There's nothing like a 27" screen to bring the circuit to life!

And, yes, I know the AD2 is pricey.  But it's a heck of a lot cheaper than the equipment it would take to duplicate the functionality.
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