dysfunctional 555?

[Elie]

Don Lancaster:

February 12, 2007

• • I continue to be amazed by the requests on the
    electronic newsgroups for circuits using the
    horribly obsolete and dysfunctional 555 timer
    and other bits and pieces of CMOS logic.
    
    I suspect this is mostly lazy students in woefully
    outdated electronics courses. These days, of course,
    it is ridiculously cheaper/faster/better to use a
    PIC instead.

Why does he call the 555 dysfunctional? Also, what does everyone think of his whole comment?

[Carl-NC]

Don Lancaster is one of my favorite columnists of all time. But I wholly disagree with him on this. I can build a 555 pulse generator, with variable duty cycle and variable frequency, in 2 minutes on a breadboard. Besides the 555, 2 pots and a cap, and maybe a diode. No programming needed.

- Carl

[Max]

Don Lancaster:

February 12, 2007

• • I continue to be amazed by the requests on the
    electronic newsgroups for circuits using the
    horribly obsolete and dysfunctional 555 timer
    and other bits and pieces of CMOS logic.
    
    I suspect this is mostly lazy students in woefully
    outdated electronics courses. These days, of course,
    it is ridiculously cheaper/faster/better to use a
    PIC instead.

Why does he call the 555 dysfunctional? Also, what does everyone think of his whole comment?

Hi Elie,
totally agree with Carl. I know how to program PICs and other things...but for experimenting is better to have a simple 555 ! Also easy to change timings etc...well, one can do also using in-circuit programming...but you need a computer on workbench to program on the fly the microcontroller there...so it's something that the hobbist really don't need to do...and simply interferes with true electronic testing.
When all timings are right one can chose to adbandon 555 and monostables...and switch to a PIC or something else...to avoid too components on the board, too consumption, too pots around, too more discrete components e.g. resistors, caps etc but seems that this kind of problem is really related to a "production oriented" mind --> not an hobbist!
Also today most MDs are really similar to past analog versions...circuits...so why worring about having a 555 in this kind of stuff ???
Only if one chose from beginning using MCU and e.g. ADCs ics make sense to avoid discrete timers etc at least for me, doing all the stuff in a digital way with programs.

Best regards,
Max

[Kitsune]

Don is getting old, a bit stubborn (preachy) and inflexible in his views. May happen to anybody with age. Besides, there should be a moment when pupils start to notice teacher's inaccuracies and errors, and eventually start to think by themselves, outgrow the teacher. Othervise there would not be any progress of humankind.

[Max]

Don is getting old, a bit stubborn (preachy) and inflexible in his views. May happen to anybody with age. Besides, there should be a moment when pupils start to notice teacher's inaccuracies and errors, and eventually start to think by themselves, outgrow the teacher. Othervise there would not be any progress of humankind.

Hi Kitsune,
I agree with you. But if one just need to experiment some analog circuit...and need a small timer...versatile..no programming required...why don't use a 555 ?

I think all depends on what you need...if you make a new device starting from MCU , ADC, DSP etc...no reason to use 555 or other aged devices...but if you need experimenting on very traditional circuits...well , no reason to have a pic to do the same work of a 555 and a pot. Why ??? to have a modern-trendy-looking-circuit ??? Don't understand.


I think that some people that use tubes for hi-fi know what they do...even if these components are now obsolete they are right for what they do.


Depends of what you need.
That's all.

Best regards,
Max

[Esteban]

Maybe dissapoint the old and versatile 555 because today is PIC's market, and well, they want to sell, include for very simple projects. Another cheap chip (good combination of words!) is the 4047B with similar functions of the 555, you need only 2 external components. Include frequency divider by 2:

[Carl-NC]

The 2x frequency would be handy for clocking a 7660 charge pump, which divides by 2.

[Max]

Maybe dissapoint the old and versatile 555 because today is PIC's market, and well, they want to sell, include for very simple projects. Another cheap chip (good combination of words!) is the 4047B with similar functions of the 555, you need only 2 external components. Include frequency divider by 2:

Hi Esteban,
yes I've used too in small power inverter. It has also symm not overlapping pulses.

Best regards,
Max

[Max]

Maybe dissapoint the old and versatile 555 because today is PIC's market, and well, they want to sell, include for very simple projects. Another cheap chip (good combination of words!) is the 4047B with similar functions of the 555, you need only 2 external components. Include frequency divider by 2:

Hi Esteban,
another good one (but obsolete and hard to find) is Intersil ICL8038. Has everything to give from 0.001Hz to about 300KHz square, triangle, sine waves at same time...with frequency, duty, sweep regulation capabilities. Very good shape/low distortion. Requires only few resistors/pot and capacitors. Only serious drawback is consumption.

I have only one at the moment but I use sometimes.

http://www.intersil.com/products/dev...asp?pn=ICL8038

Also useful to make poor-man function generator...

Other little + expensive are XR2206 (up to 1MHz) and MAX038 (more than 20MHz).

Best regards,
Max

[chemelec]

Hi Esteban,
another good one (but obsolete and hard to find) is Intersil ICL8038. Has everything to give from 0.001Hz to about 300KHz square, triangle, sine waves at same time...with frequency, duty, sweep regulation capabilities. Very good shape/low distortion. Requires only few resistors/pot and capacitors. Only serious drawback is consumption.

I have only one at the moment but I use sometimes.

http://www.intersil.com/products/dev...asp?pn=ICL8038

Also useful to make poor-man function generator...

Other little + expensive are XR2206 (up to 1MHz) and MAX038 (more than 20MHz).

Best regards,
Max

Personally I Like the 555.

Also the ICL8038 and XR2206.
I stock a few of the 8038 and Lots of the 2206.

PIC's are fine if your any good at Programming.
I'm Not.

[Max]

Personally I Like the 555.

Also the ICL8038 and XR2206.
I stock a few of the 8038 and Lots of the 2206.

PIC's are fine if your any good at Programming.
I'm Not.

Hi Gary,
yes I know pic programming...and I like them...but in some cases is best to avoid PICs ...I mean there is also noise generated by them. One time I forget to disable watchdog...wow...I have commutations in analog path every 1-2 seconds.
In other cases I had very big problems using pic and other MCUs too.
Now I think, for experimenting, is best to have handy, cheapy, no-programming components.
Then, after,one could switch to PIC or everything else to reduce circuit complexity.

Also if I know how to program...why complicate my life ? I don't like people that say "you must use this...or that...because is better...", just for trendy-style-philosophy. It's easier to turn a pot...instead of digit some assembly code on the fly...and also using hi-level compilers/language is everything the same...turning a pot is much easier and also faster.

PICs are also much expensive than 555 ...so Lancaster has missed the point here, I think.

I think that electronics is first FUNCTIONALITY: better is to avoid much troubles...and PICs could be a source of them, at least when testing is done.


Best regards,
Max