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Background, I'm not an electronics engineer but as a kid assembled a lot of Radio Shack (number) in One kits. I work in IT and have been using a computer since age 5. I would say on a high level near expert on computer hardware, but on the modular level, not component level.

Basically what the Arduino has taught me about electronics is:

The things that I always thought were hard are actually easy.
The things that I always thought were easy are actually hard.

Meaning that a lot of stuff you just plug 2 or 3 wires into it, and go straight to the pins and it works.
The hard part is wrapping my mind around things like taking a 2 pin component and then piggybacking a resistor across it in parallel for some particular reason.

My mind can't really comprehend taking resistors across power sources. I keep thinking, the resistor is causing some kind of short and is going to either heat up or eat the battery.

Also before the Arduino, I had never used all 3 pins in a potentiometer. I always went just two pins, middle and left. I think I sort of understand what using 3 pins is doing... Pulling a pin up or down rather than just down vs "not down" it makes sense now that I understand that pins on integrated circuits can or will float when not pulled up or down.

I really had thought I understood voltage vs current, but I would say only the very basic aspect of it. Arduino has taught me there's more than I thought. Voltage is sort of pushed, current is drawn. A .5 amp light bulb is not necessarily going to explode if it's on a 100 amp source if the voltage is the same as long as it is working correctly.  If it fails or shorts internally then yes it might blow up but that's when you need a fuse or circuit breaker.

Can you imagine what the American space program would have been like if you could have gone back in time to the beginning of it and handed them a box full of Arduinos and a method of programming them and basically said "These are what all the pins do, this is the programming language, don't ask how it works, it's all top secret." ?

[Reply #1 on:]

Also before the Arduino, I had never used all 3 pins in a potentiometer. I always went just two pins, middle and left. I think I sort of understand what using 3 pins is doing... Pulling a pin up or down rather than just down vs "not down" it makes sense now that I understand that pins on integrated circuits can or will float when not pulled up or down.

Well maybe I can help with a better 'pot' explanation.

First there are available two terminal variable resistors called a rheostat (that's probably a brand name) that by moving the knob you can change the wiper pin to the other pin's resistance from 'zero' ohms and whatever the devices maximum resistance value is, say 10K ohms. A pot (potentiometer) is a three terminal device that has a third pin that is called the wiper terminal. If you wire the wiper terminal to one of the end terminals you will have converted your potentiometer to be a two terminal rheostat control. But by using all three terminals on a real 3 terminal pot one has the ability to form a voltage divider with a movable output voltage equal from ground to whatever voltage is applied to the other fixed terminal, which is a very useful function used in many circuits.

 The first major milestone to getting a real good start in understand electronics is to really master ohm's law. And by master I don't mean to just memorize the three basic formula that make up ohm's law, E=IxR, R=E/I, and I=E/R, but to really understand what that means and how it defines the interrelationship and interdependency of voltage, current, and resistance with each other. Without that true understanding it makes moving on to the more complex fundamentals of electronics all the more difficult. Electronics is really not a rule based subject based on pure memory of such rules, but rather the understanding and application of fundamental principles into practical components and circuits.

Lefty