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Is the 555 still a viable IC?

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baldurn:

--- Quote from: Zero999 on February 19, 2024, 07:12:06 pm ---
--- Quote from: factory on February 19, 2024, 05:39:22 pm ---Bigclive found a new product using the 555 only 2 years ago.

David

--- End quote ---
It uses the 555 as a Schmitt trigger oscillator to generate a sawtooth, which compared against a potentiometer, using a comparator to generate PWM. I would have used a quad op-amp/comparator IC: one channel for the Schmitt trigger oscillator and the rest as comparators for the PWM. The LM339 will directly run off 24V, so no voltage regulator is required.

--- End quote ---

The 8 pin ATTiny212 would have done the job with one chip instead of three chips and a much simpler schematic. You would configure three pins as ADC to sample the potentiometers and three pins as PWM output. The remaining two pins are VCC and GND.

julian1:
The pattern of having analog comparators, controlling the inputs of a S/R flip-flop for stateful behavior, is really common in things like smps etc. 
I feel like the Camenzing's 555 would be more general purpose/have higher utility, without the 5k/5k/5k biasing divider, which needs to be worked-around when a circuit that is not a simple timer/oscillator is called for. Although it's possible there is also a pin count constraint. 
Perhaps someone made a variant?

Gyro:
There is the Control pin (pin 5) which gives direct access to the other input of the Threshold comparator, but this also interacts with the Trig comparator other input via the 5k/5k divider formed by the bottom two resistors in the internal chain. There was never any variant without the resistor chain that I'm aware of though.

schmitt trigger:
A classic book, copyright 1976. Although this particular edition is 1978.

tooki:

--- Quote from: xrunner on February 19, 2024, 01:34:55 pm ---How about the individual learner / hobbyist? How many are there? 10 million worldwide? Maybe they buy five ea. on average because the price is very low. Now we're talking 10 million entities buying 50 million 555 timers per year.

The teaching institutions buy even more. Maybe the institutions that use them buy 5000 555 timers ea. (on average) and the number of institutions are 10,000. (we're talking worldwide now). So they all buy 5000 * 10,000 = 50 million 555 timers.

Now we are up to 100 million 555 timers per year just for the hobbyists / learners / teaching institutions. That's 1/10 of the mysterious One Billlion number. The rest is industry buying. If we want to agree the 1 billion number is really less now, I can easily support my claim that hobbyists / learners / teaching institutions buy many of them. But I have no way of knowing how many they buy, but like the Drake equation I can get the answer I want if you give me a little time to play with the numbers.  :D

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I’d guesstimate those numbers at something like 10% of that. Me, I haven’t bought a 555 in years — and that time included my 3 years of electronics technician training. In that, we did use the 555,  but because we breadboarded them, almost all of them were kept for reuse, so very few being purchased. These days, for better or worse, in education you end up simulating more than testing actual hardware.

And I don’t anticipate buying any more 555s because I think there’s a better solution for almost every application. At least that’s been the case so far.

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