Questions from learning from some simple circuits

[Om_Audio]

Just lost a post using the back button- grrr.

Anyway- had fun tonight learning from a broken night light and solar UV light. Got clips for my DMM probes- sweet! Also have parts for a testing rig, need to plan that out and whether I will need one with LEDs, 9v, and a 3PDT switch like I have seen elsewhere.
I also tried drawing my first basic schematic. The night light pcb has no ground plane and seems to be basically point to point. Was really fun and more challenging than I anticipated at times. Flipping the circuit over was confusing at times trying to id the component then the traces underneath. I found I could hold it up to a light and see through, that was helpful.

Amazing to see wall socket power dealt with by tiny components. How can same socket that can power a 1500 watt heater not just burn up a 2.5watt bulb with only a transistor, photocell, and diode in the way?

-Tranny doc says KGA, why is that? K-collector, G-gate, A-emitter? Is that right?
-DC flows in one direction? How does this work when it reaches an intersection? Flows towards ground?

Anyway- pics:
https://docs.google.com/folder/d/0B4HE5N1xRnHJZW5IRlR5aExYdXc/edit

Last, if anyone can read this old post and help me understand how electricity or DC more specifically acts in a circuit I would be most grateful. The last post gives my suppositions or analogies.
http://www.madbeanpedals.com/forum/index.php?topic=3941.0

Thx,
C