Re: 555Timer ("show me the money")
> [EMAIL PROTECTED] wrote:
> Show me a "quad" 555 in one package. There was one once
> actually, the 558. Was sold by Radio Shack. Can't find
> them anywhere now, though.
The 558 is still around but will more rapidly die out/off
because of their function/logic limitations compared to the
standard 555 design.
The LM558 Quad timer has significant differences when compared
to the 555 and 556 timers. The biggest issue is how individual
LM558 timers are not designed to operate in the Astable Mode.
> Show me a 555 used as an audio amp.
Well, although not the most practical path... the 555 output
will directly drive a speaker. We see it used in a number of
code practice and audio oscillator applications. Probably
wouldn't be ultra hard to trigger or modulate the chip with a
lower level signal... and wha'la! an audio amplifier.
> I can build a complete COR/hangtime/TOT/audio interface using
> one LM324 (actually, nowdays I prefer the TLV2374 - less
> crossover distortion & better rail-to-rail performance).
The question is... can you actually hear the difference in
performance? or in most common basic op amp low frequency
audio circuits, would you actually be able to see the
performance with basic test gear?
Hamtronics did the same functions in their COR-2 circuit using
two 8-pin dip 555-Timer Chips, a few bipolar transistors and
similar misc parts. The physical foot print is about the same.
Building these type of circuits is a real hands-on electronics
education well worth the time and money. Many of you wonder where
the "guru types" learn this type of electronics... Build a Hamtronics
COR-3 kit and you'll know a lot more about how this type of
electronics works in the real world. Hard to find this type of
education in any school.
> 555s/556s certainly have their place, but for something as
> simple as the above I find the rail-to-rail op amp more
> convenient & straightforward.
> Bob NO6B
The Hamtronics COR-3 is the op-amp version of the circuit you
describe and a later production design versus the COR-2 555
Timer.
Although the COR-2 information is not on the Hamtronics web page
manual download section the complete COR-3 Manual (with circuit
diagram) is available free. Well worth a look if you'd like to
see how Hamtronics does it...
cheers,
s.
