You mean huge *lie*.
Also, when something is sourcing or sinking 200 mA, it doesn’t mean that it will necessarily by clearly at a logic 1 or logic 0 voktage-wise.
Also, when something is sourcing or sinking 200 mA, it doesn’t mean that it will necessarily by clearly at a logic 1 or logic 0 voktage-wise.
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I simply don't get why people use the original '555 at all, its shoot-through problem is well-known and frankly horrible - its even explained in the original edition of Horowitz and Hill dating back to the 1980 so there's no excuse 🙂
One of the CMOS variants is usually a better performer, especially in an audio environment where large supply current spikes of 100+mA will likely create very audible interference.
One of the CMOS variants is usually a better performer, especially in an audio environment where large supply current spikes of 100+mA will likely create very audible interference.
And... going back to post #1 and the NE555. I just had to try this to prove to myself it does do what is claimed and I think it does.
Simple 555 astable running at about 0.1Hz on 12.5 volts and it could put 10.83 volts across a 56 ohm to ground (so 0.193A) and with the load swapped over to sink into pin 3 it could develop 11.25v across the load (so 0.2 A).
Simple 555 astable running at about 0.1Hz on 12.5 volts and it could put 10.83 volts across a 56 ohm to ground (so 0.193A) and with the load swapped over to sink into pin 3 it could develop 11.25v across the load (so 0.2 A).
The internal schematics are very odd, all npn output and some pnp inputs, that must have been a challenge in their day.
Looking at the Reset input, you can see why it was always temperamental
Designing Analog Chips, by Hans Camenzind, chapter 11, has some notes by Hans about why he did what he did.
Designing Analog Chips by Hans Camenzind
"To this day the 555 has been the best-selling IC every year, copied by numerous companies. Except for a CMOS version, the design has never been changed. Looking at the design now, 33 years later, there are many areas where it can be improved with the design techniques we have learned since..."
As a chip it has its place... but I almost never drive significant current with logic ICs. I know you can, but if I have the board space and budget I like to use a dedicated transistor driver.
Been quite a while since I designed in a 555 though...
Been quite a while since I designed in a 555 though...
I use the faster CMOS 555s (not the ICM7555) quite often still for various nefarious purposes. I can't recall the last time I used one of the original bipolar devices (well, maybe 40 years or so ago)....
I'm using about 25 of them for a cheap organ project for my son (complex polyphony) or only one, plus envelope generator I am yet to build (less complex monophonic)
I also have a boat load of 8038, so will probably do something similar with them.
All just for laughs really.
I also have a boat load of 8038, so will probably do something similar with them.
All just for laughs really.