>> Really? I thought it was 4.5V - 5.5V for logic 1...
> 
> http://www.twysted-pair.com/74xx.htm

OK, that's interesting. Wikipedia claims

"All standardized common TTL circuits operate with a 5-volt power 
supply. A TTL input signal is defined as "low" when between 0 V and 0.8 
V with respect to the ground terminal, and "high" when between 2.2 V and 
5 V.[8]"

And yet, note [8] refers to the link above, which contradicts that 
statement. I'm confused...

> Note that the output from one chip can actually only drive 10 inputs, I 
> thought it was much higher than this but maybe I was remembering some 
> other chip series.

Well, I'm unlikely to reach even that number...

>> http://en.wikipedia.org/wiki/Hi-Z
> 
> Yes, exactly. Did you read the 2nd paragraph there? ;-)

Damnit, the whole *point* of digital electronics is to obviate the need 
for resisters and complex stuff like that. A digital circuit should just 
be an arrangement of logic gates, and nothing else! >_<

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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