6V to 12V question

[quantum]

 http://www.electronics-lab.com/projects/power/014/index.html
My questions are from this site. Are all transistor's code labeled on themselves so you can perhaps indentify them on a circuit board? Such as those transistors in that site. What does the term "tordial" mean in this sense? Where do you insert the 6  and 12 volt terminals? I know where the you insert the the positive terminals of each, but where do you put the neg. terminals? Do I just put each negative terminal on the neg. bus line?

[MP]

The arrows pointing down are the schematic symbol for your ground plane, which is also connected to the minus side of your battery in this project.

MP

[quantum]

 That makes sense. I beginnning to become really familiar about ground and how all neg. terminals are just somewhat nuetral in some way. What about being able to identify transistor only by looking what is printed on it.

 I made the flashing LED circuit work with your guyes help about the attaching the diodes to it. I changed the res. to make them flash at the rate of which a reseted digital clock blinks. http:// 12:00 http://

[MP]

Yeah, transistor markings are a hard one. Depends a lot on the manufacturer. Sometimes they just have a factory code on them if you buy them in bulk quantities. You are lucky when you get the ones with the part number and company insignia stamped on them. Take a look at the surface mount ones. There is just not enough room to say it all.

MP