"555 Timer is soooo versatile", really?

[Alex Eisenhut]

Well, sure, you could use it as a timer and it is versatile, but not very modern.

[Electroplated]

Used two 555's in a new linear PSU design a few weeks ago, one 555 is part of the cooling fan pwm control, the other 555 is used a simple push button toggle switch for the outputs.

The 555 is my favorite IC and I have used one or another of its incarnations since it first became available, it even features in a rather basic scope I made back in 79, using a salvaged radar crt. A 555 fed with a constant current generated the linear saw-tooth for the sweep and another one provided flyback blanking. ( it still works albeit the tubes rather dim now )

 think I will using them for a long time seeing as I have 470 of them due a slight mishap on my ordering sheet years ago, was 500 but I have used a few since then 

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[Ranayna]

I tore down an LTO-4 Drive made by IBM some time ago.
I was somewhat surprised to see not one, but two 555 chips on the main board.
Considering what else is all on that board, the 555s seem very anachronistic.

[JPortici]

(Also, if you ever have a safety-critical LED, do not blink it on-off. Blink it bright-dim. That way glancing at it can never show it as totally off.)

but then you have scores of users that complains that it's always on and think that dimming is a problem because they find it strange

but to stay on topic, i will use it in a future product to implement a hardware watchdog. In the event the MCU is stuck one part of the circuit need to be bypassed. This is going to be done via a relay that is controlled not from the MCU directly, but from a monostable, retriggerable multivibrator that will be implemented with 555

Also the OP should take one of the many 555 cookbooks and see what you can do if you get creative

[jonpaul]

in 1970s..1980s

variable siren, bike horn
ADC DAC isolation power supply driver
frequency..period to analog converter


See Don Lancaster's IC timer cookbook, 1970s

Jon

[dastructhm]

Used two 555's in a new linear PSU design a few weeks ago, one 555 is part of the cooling fan pwm control, the other 555 is used a simple push button toggle switch for the outputs.

The 555 is my favorite IC and I have used one or another of its incarnations since it first became available, it even features in a rather basic scope I made back in 79, using a salvaged radar crt. A 555 fed with a constant current generated the linear saw-tooth for the sweep and another one provided flyback blanking. ( it still works albeit the tubes rather dim now )

 think I will using them for a long time seeing as I have 470 of them due a slight mishap on my ordering sheet years ago, was 500 but I have used a few since then 

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a toggle switch with a 555? I wanna learn its schematic.

[Geoff-AU]

I just bought some 555 for a project - they go up to 2.1MHz!

I sure can't count that fast!

[Berni]

Yep i seen 555 timers in products. Things like turbo buttons on game controllers, beeping things, RS485 repeaters as TxEnable recovery, PWM signal generation etc...

However most electronics products have gotten much more complex to a point where other chips can often do the job of a 555. Like as soon as there is a microcontroller in there it makes sense to let it do all the timing.

The neat thing about a 555 timer is the versatility to be able to make it to so many different things depending on how you wire it up. Sure it takes a good deal of passives around it to actually make it run, but doing a lot of these tasks with discrete transistors or even opamps would take even more components.

[Siwastaja]

but then you have scores of users that complains that it's always on and think that dimming is a problem because they find it strange

This. If you have to go so far that on/off blinking is not indicative enough, then the classic solution is two lights that blink alternatively. This has the benefit of broken light being instantly obvious while the other one still provides indication.

[TheUnnamedNewbie]

I think it will be rare when using one in high-volume production is the 'right' choice (things change in low volume when time to design >>> cost of actual parts).

That said, my students still love them and I suggest them a lot, lots more hands on than some 'digitalWrite()' funtion that goes on and off a lot.

[Warhawk]

People say its application is huge. Yeah. I know. Like its astable mode, bistable mode, etc, just to blink LED's. Okay, but...that's it?

In real world, what do engineers use the 555 Timer for? in real products, I meant.

555 timer still pop-ups frequently. I can confirm that you can find it even in new electric vehicles. There are many reasons why. 555 time comes from many sources, is cheap, does not require programming during production, functional safety and it often "does the job".

[Electroplated]

Used two 555's in a new linear PSU design a few weeks ago, one 555 is part of the cooling fan pwm control, the other 555 is used a simple push button toggle switch for the outputs.

The 555 is my favorite IC and I have used one or another of its incarnations since it first became available, it even features in a rather basic scope I made back in 79, using a salvaged radar crt. A 555 fed with a constant current generated the linear saw-tooth for the sweep and another one provided flyback blanking. ( it still works albeit the tubes rather dim now )

 think I will using them for a long time seeing as I have 470 of them due a slight mishap on my ordering sheet years ago, was 500 but I have used a few since then 

--

a toggle switch with a 555? I wanna learn its schematic.

This is the toggle switch, taken from one of my project diagrams. The 'protect' connection disables the output so long as its held low, in this circuit its part of the over volt tracking and over heat protection section of the psu but could be used for other purposes.
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[b_force]

Lately I have been going towards just logic gates (again!) instead.

It just takes one inverting schmitt bugger to do already many things like PWM drivers, led drivers etc etc
Do this with like a NAND or so and possibilities grow fast.

A 555 is just a very jelly bean part with so many applications (even a buck, boost converter is no problem).

These days there are just many alternatives that are very affordable.
Still the majority of those more "specialized" still contain parts that can be found in e 555 as well.

But to answer the question, no I very rarely use a 555 anymore these days.
In the past it was kinda my goto for any kind of prototyping or DIY projects for many things.

[JPortici]

Many analog synthesizer use a 555 for the AD/ADSR/more more complex envelope generators (rene shmidtz, ray wilson and yves usson websites come to mind).
However many implementation didn't include a very important element, the buffering of the 555 RC output before going into the other stages. The envelope time parameters affected each other.

[james_s]

People say its application is huge. Yeah. I know. Like its astable mode, bistable mode, etc, just to blink LE5D's. Okay, but...that's it?

In real world, what do engineers use the 555 Timer for? in real products, I meant.

Now? Relatively little, they're a vintage part with far less use than they once had although they do still pop up now and then.

In the past they were used all over. Both the Wells Gardner and Amplifone color vector monitors used in millions of Atari arcade games used a 555 in the high voltage supply for the CRT. Dozens of early arcade games used 555's to generate sound effects. Lots of 80s-90s toys used them to blink lights or make sound effects. They've been used in time delay relays, lamp flashers, sirens and alarms, motor speed controllers and countless other things.

[james_s]

People say its application is huge. Yeah. I know. Like its astable mode, bistable mode, etc, just to blink LED's. Okay, but...that's it?

In real world, what do engineers use the 555 Timer for? in real products, I meant.

I've seen it be used in 8 bit atari computers for an turn-on-reset circuit

That reminds me of another famous use, as a joystick or pot ADC, Pong was a notable use of them. I think some 8 bit computers did too.

[james_s]

MCU everywhere is the best chance for obsolescence of products. You fry the MCU, you can trash the product, as usually you cannot get the firmware.

Parts do not just fry. Microcontrollers are extremely reliable.

I've had parts just fry, sometimes there was some unknown underlying cause, other times I accidentally fried something by shorting it or some external fault. I've also had microcontrollers fail, a bad voltage regulator can kill them, and I've had a cascade failure where a mosfet blew and the HV tracked back and blew up the micro. Lighting strikes blow up loads of stuff in areas that get a lot of those. Failed programmable parts are a serious problem that hinders repair efforts.

[james_s]

That's a big problem as they see it though... the manufacturer usually doesn't want you to repair the broken product, they want you to buy a new one.  If manufacturers made their products easily repairable, there would be little incentive for you to replace it and their profits would suffer.  Make it diffcult/impossible to repair and replacement is about the only option.

It doesn't matter at all. The people who are going to try to repair some consumer device, at least one that costs a few hundred dollars or less even if it is made such that it is very repairable are statistically insignificant. I can't count the number of things I've been given that had absolutely trivial faults yet the owners replaced them rather than try to repair it or have somebody repair it. There is absolutely no reason for a company to deliberately make something difficult to repair because 99.99% of customers are just going to throw it away when it breaks anyway.

[jonovid]

just one of many uses

[JPortici]

MCU everywhere is the best chance for obsolescence of products. You fry the MCU, you can trash the product, as usually you cannot get the firmware.

Parts do not just fry. Microcontrollers are extremely reliable.

Idiot user does idiot things such as applying overvoltage (willingly or by mistake). Unless it's an old design that used microprocessors with external memory so you can find someone that has read the firmware, the only one that can repair is the manufacturer

[Neomys Sapiens]

2 or 3 years ago, I had to come up fast with a test aid for our service technicians which is used to determine
- whether the 1PPS-pulse from a GPS receiver is strong enough at the end of a cable run
- whether it appears regularely and without interruption
= 1 comparator with a 'buffered' 10-turnpot to adjust the level threshold precisely, NE555 as missing pulse detector (retriggerable monoflop), remaining half of the double compatator as a latching indicator. Done.

[amymcneil]

I'm using a 7555 in a widget I'm building for a friend of mine. I need a ~200 millisecond pulse with a 1Hz repetition. Also needs to run on microamps. And be able to drive a mosfet directly. The 7555 fills the bill perfectly for this. Cheap, available from multiple manufacturers, no firmware (there's no micro in the widget).

In the past I've used them for timers, threshold detector/latches, one shots and as an AC mains zero crossing detector. Yeah, it's ancient, but there's a lot you can do with the bits inside of one.


Nice Tek 555. Mine isn't as pretty - still waiting for me to work on restoration.

[Alex Eisenhut]

Nice Tek 555. Mine isn't as pretty - still waiting for me to work on restoration.

That's not mine but I have a 547 and a 567. Even I have to draw the line at a 555. Unless there's a free one in Montreal... Just too big and onerous for me otherwise.
Kinda envious though.

[Electroplated]

Ha, found another of my 555's in a led garden light, forgot about it, not surprising as it was over five years ago when I build the circuit, its just a crude and rude drop down switching reg that drops the 12v to 5v for the led. Dam LED gave up the ghost a few days ago, Once the led was swapped out, the light sprung back to life, not very exciting I know, but still very much 555 related !

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[james_s]

Ha, found another of my 555's in a led garden light, forgot about it, not surprising as it was over five years ago when I build the circuit, its just a crude and rude drop down switching reg that drops the 12v to 5v for the led. Dam LED gave up the ghost a few days ago, Once the led was swapped out, the light sprung back to life, not very exciting I know, but still very much 555 related !

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I wonder if it's actually any more efficient than just using a resistor in that application. Or 2-3 LEDs in series with a resistor. Most garden lights have a switching converter because they're stepping the voltage UP to run a white LED from a single AA cell.