
2-bit full adder using just thirty six 555 timers - fogus
http://hackaday.com/2011/02/28/2-bit-full-adder-using-just-thirty-six-555-timers/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+hackaday%2FLgoM+%28Hack+a+Day%29
======
sagacity
Whoa !!! Cool!

Having discontinued hardware hacking (not by choice) more years ago than I
care to admit, I didn't know that those cute li'l 555s are still around !

Speaking of which, are the good ol' 741 op-amps still going too? Just curious.

(This sure brings back some fond, old memories.) :-)

~~~
fooandbarify
741s are still going strong! In fact, as far as I can tell (electrical
engineering student) they are the most prominent op-amp in use by far.

~~~
HeyLaughingBoy
No. Not even remotely true.

741s are around in books and in EE labs because they're what people used back
in the 70s' (and perhaps cause the lab bought thousands back then). Since
there was such a huge volume of designs produced using them, you can still buy
them today.

No engineer in his right mind* (no disrespect intended: I know you're a
student) would use a 741 for a new design today. They are slow, imprecise
power hogs, and require bipolar supplies to get them to do anything. Even a
jellybean LM324 outshines them.

(*) if anyone can counter this statement with a useful application of the 741
where a more modern and cheaper opamp wouldn't do better, I'd be really
interested in seeing it.

[edit] It looks like the 741 has been improved quite a bit since I last looked
at it. So I don't need to be so harsh, but I still can't see any good reason
to use it for new designs in 2011.

~~~
fooandbarify
Wow, well I feel a bit dumb for answering with such certainty then! Apparently
I have been misled. Thanks for setting me straight!

------
oconnore
Why? Is there something special about using 555's that I don't know about? A 2
bit full adder is a really simple circuit...

~~~
sagacity
Yes. What you're saying is probably because you don't (yet) know what uses can
a (simple circuit built around a) 555 be put to.

Back in 1985/6, I built a (simple, ham) radio transceiver mainly utilising
555s, 741s (and some crystal oscillators + other discrete components) with
which, I _actually_ communicated with people from more than 50 countries
around the world, without spending the cost of international phone calls
(which was prohibitive then).

Edit: And _long_ before I did that, other hackers used to do similar - or even
better - things. :)

