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Conventional Current What?! Electrons Flow the Other Way!

I did not do too well in the one basic electronics course I did have in university.  The ability to conceptualize everything physical and how it all interacted with each other served me well... in my drafting class.  When it came to electronics, the one thing that irritated me so much was that all the equations were written for conventional current when the 'flow of electricity' was from positive to negative.  But that's not true!  The flow of the electrons (or electricity) is from negative to positive.  The electrons are repelled by the negative charge of the electromotive force, ie. battery, and are attracted to the positive end through the circuit.  I was ok for DC current because the equations worked, I just had to put negatives in the right place.  When AC current came around, I was hopeless as using negatives in the equations simply did not work.  Now I just imagine it as a hydraulic system instead.  Now it makes much more sense.

Given my ineptitude at electronics I went to the local electronics shop, pleaded my plight and purchased this:

Learning Electronics Kit


This is a starter electronics 'toy'.  I purchased the one with the breadboard as I knew I would use it later.  I never did get through all the exercises as I took it apart for all the various components.  In the photo, it looks like I was learning to use a transistor.  The reason I had the power hooked up to the 7-segment display was because I blew a bunch of the other LEDs as I didn't know I needed a resistor.  Should have read the manual.  I also managed to blow up a couple NPN transistors while learning about darlington pairs.  Darlington pairs, are two transistors where the emitter is connect to the base of the second so as to switch more power.  This is done usually to allow small voltages / currents to switch higher voltages but often the transistor that can switch the higher voltage requires more than the usual 3.3V or 5V logic intergrated circuits runs on.  More info about darlington pairs can be found here. If you do make a darlington pair from two transistors, remember to limit the current going to the base of the second transistor by using a resistor between the emitter of the first transistor and the base of the second, or between the collector and the voltage source (VCC) of the first.  This way, your transistors won't explode like mine.

 Darlington Pair Circuit

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