>> Funny, I thought I *already* had a basic knowledge of how circuits 
>> work...
> 
> The circuit diagram you posted here makes it look like you don't.

Well, I noticed it wasn't going to work *before* I assembled it, right? ;-)

>> I guess what's throwing me is this new "logic low = negative" thing. 
>> I'm used to thinking of logic low as "nothing connected here".
> 
> OOC why are you used to thinking that?

I guess it's the way most books refer to circuits as "on" or "off". 
Usually if something is "on" it means it's connected to a power source, 
and if it's "off" then it isn't connected. That's how, e.g., a light 
switch works. It doesn't connect the output to the other pole when you 
turn it off, it just doesn't connect it to *anything*.

Of course, strictly speaking, logic high and logic low can be 
_anything_. So long as it's documented what they are and all the 
circuitry is expecting the same thing, it'll work. But still, most 
people casually refer to "on" and "off".

>> Uh, no, even I'm not crazy enough to want to do that. :-P
> 
> It was just an example, you might one day want to control a motor, a 
> brighter lamp or a heater or something.

Fair enough. But my immediate plans only run to wiring up lots and lots 
of logic gates, and observing their output.

>> 3. Relays presumably use about 100x the current that an IC can supply.
> 
> Hehe no, I've got a tiny surface mount IC here that is driving 6W of 
> LEDs directly.

Sure. But I'll bet it isn't a general-purpose logic gate. It'll be some 
special driver IC or something.

>> 4. PROFIT!
> 
> Huh, what are you planning to sell? No more free advice :-)

OOC, what's your hourly rate?

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