Start: 10:00

• Took me a while to figure out where the power jack footprint was in the pad2pad software.  I ended up having to drag it in from the folder as I couldn’t find where it was in the UI.
• Apparently there are two types of power jacks.  I have to make sure we get the one where the center pin is positive.  Some have negative pins
• Did an experiment with testing currents of both the power supply and our AC adapters.  i = V/R and the resistance formulas seems like a simple enough equations but somehow I missed the concept behind it.  Basically current is more like a pull caused by the lack of resistance.  The load resistor is what pulls current into the loop.  This could technically be anywhere in the circuit but the placement can have a great affect on what you are trying to do.  In the case of my test circuit, this resistor is right before the LED in order to protect it from getting too much current.  If I branch off from the node where the positive terminal of this resistor starts and add another circuit in parallel, this does not change the properties of the loop with the LED in it but makes the current pulled by the entire circuit with the new branch increase.
• A key concept I keep forgetting is that current flows from negative to positive.  This means that a load resistor on the positive side of a circuit is  not really preventing power from going in, but pulling it from the negative side in.
• Started drawing the circuit for the reheostats and the pre-amps.

End: 6:00