Thanks to everyone for helping me so far.  I've read and tried to understan=
d each post, and Google the bits I didn't understand.  That graph was great=
..  I was trying to make a similar one with excel but failed.

I don't completely understand volts and current, but I now have a semi-work=
ing knowledge of V/R=3DI.  And I think I know enough to work with it.  Arme=
d with help from this group and google, watching youtube videos with exampl=
es, often using an oscilloscope, have helped me enormously.  (I am saving m=
oney for a proper one, not the cheap USB one.)

One thing I've learned is that batteries are "different."  I don't remember=
 the details, but they don't fit into my imaginary images of how electricit=
y works.

A large, charged capacitor in fact does fit my understanding.  (A big one r=
eally can kill.  I saw a demo of what one can do on youtube.  It melted a d=
ime.)

Another thing I've learned a bit more is why a circuit is built the way it =
is.  Not only do you work with individual parts, resistors, capacitors, tra=
nsistors, etc, but also with blocks of parts.  For example, on a youtube vi=
deo he showed on the oscilloscope a noisy DC input current.  Then he put in=
 a capacitor and I could see how it got smooth.  And resistors and capacito=
rs in a certain way do specific things.  Diodes in certain configurations, =
and so on.  In one place I learned that two resistors in the right place wo=
uld convert a +5v to +3v for a Raspberry Pi.  I assume that in this particu=
lar case a voltage regulator was a bit overkill.

Motors pose unique problems, which I saw on an oscilloscope, so you guys kn=
ow just to put these pieces here and there, and it fixes it.

I thought that learning all about each component was all I needed (like in =
the beginning electronics books, Forrest Mimms is my favorite.) Wrong.

I've observed a lot with the bench power supply.  On simple DC motors, incr=
easing the voltage increases the speed, while increasing the amps increases=
 how powerful it is.  That makes sense.

But on the other hand, on a more complex motor, the bench power supply woul=
dn't go over 5 volts,  no matter where the dial was.  But increasing the am=
ps increased speed.  That was a bit weird.

Now the simple math makes more sense when I understand how the parts work t=
ogether.  I could calculate how big a resistor to use with an LED, but I th=
ink that 220K is about normal.

Someone gave me a raspberry pi which is why I'm getting into this again.  I=
t's quite fun trying to control things using Linux rather than PIC assemble=
r.

Thanks again.
Lindy

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