|
![](/i/fill.gif) |
> 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.
> 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?
> If you were making a bunch of logic out of switches with either connect or
> don't connect a wire to the positive rail, everything would be quite a bit
> simpler. (E.g., connecting the output of two gates together couldn't
> possibly create a short-circuit condition, since each output is connected
> to the same battery terminal or to nothing at all.)
This doesn't work, because as soon as you connect a "not connected" output
to something, it becomes "connected" and will have a specific voltage. The
severely limits how many things you can connect to a single output.
> 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.
> 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.
> 4. PROFIT!
Huh, what are you planning to sell? No more free advice :-)
Post a reply to this message
|
![](/i/fill.gif) |