|
![](/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.
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?
Post a reply to this message
|
![](/i/fill.gif) |