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Rendered at 16:50:00 GMT+0000 (Coordinated Universal Time) with Vercel.
PDF version here https://worldradiohistory.com/UK/Bernards-And-Babani/Babani/...
Fun fact: his original concept needed 9 pins and therefore was going be forced to have a 14 pin package. A late epiphany got it down to the 8 pin version we know today.
One nice thing about the 555 is that at least it aged well and still is very usable in those beginner tutorials. Unlike for example the uA741 which no one should use.
I'm curious about this claim. It's certainly easier to just wire up a modern microcontroller, but is there a better option that involves no software and is likely to still work the same today as it did 50 years ago?
For that matter, a 16 pin CH32V003 can emulate a vast array of 7400 series devices as long as you don't need ns timing — no problem for µs. It's also cheaper.
Because people are too cheap (or fail that hard at basic analog electronic control) to get a proper single-pole single-throw switch with a pair of MOSFETs in a monostable mode, or use an S-R flip-flop latch to debounce, or even a very simple R-C filter circuit.
"Throw a microcontroller on it and call it a day" is the surest sign of someone not properly educated in electronic engineering.
If you live under a waterfall you'll use 1000 gallons of fresh water pumped at blasting high speed to wash a cup.
We live under a waterfall of cpus and gates in general, and organisms don't care if their environment is perverse. A thoughtless organism will happily consume 1000 units of a free resource just to get 1 unit of some other non-free resource.
And a lot of humans are the worst. Thinking beings who elect not to care about anything like that. Like spammers that operate simply because sending email is free for the sender. They get almost nothing from it, and it costs everyone else a lot, but it costs them even less than the tiny bit they gain, and the external costs don't matter to them the tiniest bit.
But the environment is perverse, created by economies of scale and Asian slave labor and the push for advancement for it's own sake which makes existing useful things artificially low value by being "obsolete".
A software version of that might be making apps with Electron. It doesn't matter how much cpu and ram and disk and general mass of tech stack it takes to make some trivial app. The developers precious time outweighs all other considerations. If they can make the app in a few minutes with no effort instead of a few hours, it doesn't matter how much of everyone else's resources they consume since their time is valuable and 1M other people's cpus are free.
'Grab laptop, fire up IDE & plug in programmer cable' vs. 'configure the circuit using a soldering iron'. Both have their place.
But in terms of cost, a simple microcontroller is usually cheaper than a 555 nowadays, often doesn't require external components, and so even if all you wanted was a single function like an edge-triggered pulse, or generate a single frequency, it probably still makes sense to use a microcontroller from a board design perspective. As soon as you want anything slightly more complicated, odds are you can replace a ton of other circuitry on the board with that single chip and a small program.
Because nothing is faster and more responsive than direct hardware logic.
"a simple microcontroller is usually cheaper than a 555 nowadays, often doesn't require external components,"
Often? Every UC I've ever used has required a whole slew of caps and resistors just to get the thing to take in operative firmware through a programming port. Even the simple light flashers for vehicles that I've made using a UC and accelerometer need at least two caps and two resistors to make a proper circuit that allows for flashing info to the controller.
"so even if all you wanted was a single function like an edge-triggered pulse, or generate a single frequency, it probably still makes sense to use a microcontroller from a board design perspective."
Frequency generation? Inductor, capacitor, input voltage. Zero UC required and guaranteed to be cheaper.
"As soon as you want anything slightly more complicated, odds are you can replace a ton of other circuitry on the board with that single chip and a small program."
And accomplish things at a glacial speed that a basic hardware-only solution would've solved. As an example - BOSS pedals have basically zero latency because it is all analog. All these newer Line 6 and POD and other digital FX pedal makers have horrible latency, some I've measured past 50ms (almost as bad as trying to live-monitor a Windows Audio device.) It has been this way for the over 30 years I've been playing guitar.
Most times, raw hardware with zero software is THE way to go. Anything else is just a performance loss.
> Often? Every UC I've ever used has required a whole slew of caps and resistors just to get the thing to take in operative firmware through a programming port.
ATtiny for example. Many others only requiring an external capacitor, and complaining about a decoupling cap on a chip replacing a 555 that also needs an RC network to function seems rather petty.
> And accomplish things at a glacial speed that a basic hardware-only solution would've solved.
Most of these uCs operate at least 1 MHz or higher. The ATtiny85 can run at 8MHz from the internal oscillator and has an interrupt latency of 4-6 cycles. To achieve anything that's replacing something you'd do with a 555, you'd have to try incredibly hard to get latency as bad as you're describing. Perhaps they're actually doing something significantly more complicated than just replacing a 555?
See: https://mirrors.apple2.org.za/Apple%20II%20Documentation%20P...
https://www.applefritter.com/appleii-box/APPLE2/NibbelingAtT...
The joystick itself just had 1 potentiometer per axis, wired directly to the port. The port had no A/D, no timer, and no interrupt. Instead there was a GPIO and a capacitor. You discharged the capacitor with a GPIO write, and then polled the GPIO to measure when the capacitor was charged again. The number of iterations through your polling loop would be proportional to the position of the axis.
This is a pain to emulate if you aren't doing cycle-accurate emulation. IIRC Dosbox has a bunch of kludges and still doesn't get the joystick right for every game.
[edit]
To clarify the game port used a 558 (quad stripped-down version of a 555) as a schmitt trigger, so it generated pulses of a width proportional to the potentiometer position. I looked up the Apple II interface and it looks very similar, but with the caveat that accelerated versions (e.g. the IIgs) would always clock to 1MHz when reading the joystick port, compared to the PC that could run at a huge range of clocks (and CPI) over the lifetime of the port.
https://shop.evilmadscientist.com/productsmenu/tinykitlist/6...
Very cool. (Looks like it uses 26 transistors. I assume the die is similar.)
Though surprising the family at dinner with a small explosion was a much more innocent purpose.
https://www.i3detroit.org/reset-on-lan-an-ethernet-aware-rem...
It can be configured as a versatile oscillator like the 555, but it can also implement an FM modulator / demodulator, a FSK modem, a tone discriminator, a clock multiplier, a phase detector, a voltage to frequency and frequency to voltage converter a speed control loop and much more.
Not bad for a $1 chip. My circuits professor always carried a bunch in his lab coat pocket and handed them out like candy almost everyone anyone needed a circuit to do something to do with oscillation.
Maybe it could work if you used 5 timers?
https://www.digikey.com/en/products/detail/tecate-group/PBLH...
For your chosen capacitor, manufacturer doesn't even bother providing the tolerances. :) Good luck with that.
It also has 2k (16384 bits) of SRAM, allowing even larger counters.
It runs off 2.8V - 5.5V DC, so supplying power is pretty trivial. Doesn't need a crystal, though of course adding one will improve the timing accuracy.
though i take you were thinking about counting clock cycles or something in which case surely your register would overflow
Old computers often had a "carry flag" specifically to make this easier e.g.on Arm:
add r0,r0,#1
adc r1,r1,#0
addi a0,a0,1
sltiu t1,a0,1 # set to 1 if a0 wrapped back to 0
add a1,a1,t1(I just made half y'all crash out with old internet nostalgia. The rest of you are like "huh?")
More details: https://www.reddit.com/r/amateurradio/comments/1eo9ki7/xiegy...
For something feeling like a fairly specific IC, I remember seeing many projects that use it throughout the years in wacky ways - and seeing it makes me happy to know that the sentiment for this little piece is shared.
There's a lesson in there somewhere.
https://hackaday.com/2011/08/05/building-a-computer-out-of-5...
Turns one a single frequency that’s remotely close to one of the two tones of a dial tone will convince it. Wasn’t sine wave either but not a problem! 555 powered by a 9V battery.
555s are such delightful little guys. I used a pair of them, plus an ebay telephone line driver, to make an old telephone ring: https://hardfault.life/p/telco-2
One timer runs at the ~20Hz ring frequency, and the other runs at ~0.2Hz on a 20% duty cycle. The slow one's output feeds the enable line of the fast one, so you get 1-second burts of ringing, then a few seconds of silence, then ringing... just like a normal phone.
I moved about 5 months ago and haven't had time to get back to this project. The goal is to build a little phone company in a box, so I can have all my old PCs talk to each other with their modems.
building an amplifier from transistors is sometimes simpler/cheaper than using an op amp. And some designs don’t need the benefit of op amps.
On the other hand, building a timing circuit from discrete components is less obvious. And the 555 does so much of what often needs doing.
Also, the design was not patented so they were commodity chips right away.
i have the page archived, but it's called A New Solar _ Wind Charge Controller Based on the 555 Chip (2_7_2026 12
I can upload the webrip if anyone wants it