Where have you actually come across a 555 timer in the wild?

[thomastheo]

Hundreds of millions of NE555's are produced every year, but I don't seems to actually come across them very often in products I've torn down or had a peek in. I have a little drawer full of them somewhere, but i doubt all those chips are manufactured only to be destined for our collective parts bins ))

I'm very curious to see where you have actually encountered them in the wild, and the particular function they've been drafted to perform in actual commercial/industrial products. They're so versatile, there must be some interesting applications out there...

[Jarrod Roberson]

pretty much ever blinky led kids toy thing-a-ma-bob with no real inteliigence, has an equivalent IC in it. Maybe not a DIP packaged one, but the same thing none the less.

[kayvee]

Burglar alarm siren driver was a popular application.

[poorchava]

Crude (but actually useful and mass-produced) motor pwm driver.

I've also seen one on an old PC motherboard, although I don;t recall what was it used for.

[BillyD]

Back in the late 80's I had a flashing armband which took a 9v battery and had 2 red leds pointing forward and two facing rearward. It actually looked quite cool for its time as leds were still pretty rare as lighting devices (as opposed to say status indicators). So its innards consisted of your basic 555 blinky led board.

[Stonent]

I've heard that a lot of hard drives have a 555 somewhere for driving the motor.

[mariush]

Seen one in an old AT power supply on the secondary side (probably used with some other chip for overvoltage or short circuit protection). 
Don't have the board anymore (it was soldered on a header and I desoldered it and lost it).

[nessatse]

I found two 555's  on an old (pentium II, IIRC) Intel motherboard. 

I also have a (non-working)  Escort DMM that uses a 555 for the capacitance measurement

[tom66]

I've found one on an old soundcard and in a modern application one was used in a TI appnote as an LED dimmer.
Apparently over 1 billion are sold every year, presumably not all to hobbyists and education markets...

[thomastheo]

I suppose that a large amount of those 555's are destined to end up in toys and blinky led gadgets. Kind of boggles the mind to imagine how big the market is for thingamajigs, doohickies and whatsits. Perhaps a lot of those one billion (!) chips are never put in a package, but are just used as chip-on-board, also.

If you add it all up, though, there are about the same amount of transistors in one billion 555's as there are in only 5 Xbox One SoC's.

[T3sl4co1l]

Think I once saw some industrial equipment with a whack of 'em on a board.  Probably something like a chain-of-one-shot-timers circuit for generating timing and logic signals for... power control, gate drive, who knows.

A lot of the same sorts of things are chock full of CD4000 CMOS in CERDIPs.  Even current production boards.

A lot of that hardware is literally 20+ years old and still in production, hence the archaic design.

Tim

[BravoV]

Ancient HP laserjet printer Jet-Direct Ethernet add-on board that still uses thick coax ethernet 10Base2 and the "newer" RJ-45 interfaces  , remembered salvaged few TLC555 (cmos version of 555) from dumpster drivings while ago, mostly people throw them away in bulk.

Actually what I love to salvage is the BNC connectors, the older ones are quite good, all brass with thick nickel plating construction. 

Something look like this

[Jarrod Roberson]

Oh yeah, analog guitar effects pedals and other gear stand alone audio effects that need a repeating waveform/signal use them by the boatloads. Delay, flangers, echo, reverb, etc.

[Biff383]

Yes.....bike horn.....actually a 556 I think (2 in one). I got a bunch for free.

[thomastheo]

Oh yeah, analog guitar effects pedals and other gear stand alone audio effects that need a repeating waveform/signal use them by the boatloads. Delay, flangers, echo, reverb, etc.

Just checked to see if my boss flanger has one... and alas, no dice )

[PedroDaGr8]

A variety of instruments at work use them in the power supplies (old Amersham Biosciences AKTA FPLC, Gilson Fraction collectors etc.)

[David_AVD]

I saw two just the other day in a Crown high power audio amplifier.  At a guess I'd say the amp design is from about 10-15 years ago.

[Fraser]

There is an SMT 555 driving the charging LED in my new 2013 FLIR E4 thermal camera external charger. Its sole purpose is to make ther LED flash at approx 1Hz rate when charging the battery.

I attach a picture. Its SMT code is 'ZC5'

[Phaedrus]

They get used in cheap PC motherboards some times to drive the motherboard speaker. Other times they use a piezo, or on higher end boards they'll use a more advanced audio chip.

[Rerouter]

Switch-mode power supply using a 556 as the actual switching controller, (556 is just 2 555's in the same package) it had to regulate 5 rails at 120W total and i still don't quite understand how they did it (way to many passives and discrete's)

[deth502]

the device we use at work to check the depths of our test wells has one in it. 

[NiHaoMike]

Found one on a TI 5V to 12V boost converter module. It was used as a charge pump to derive the initial MOSFET drive voltage.

[poorchava]

Ancient HP laserjet printer Jet-Direct Ethernet add-on board that still uses thick coax ethernet 10Base2 and the "newer" RJ-45 interfaces  , remembered salvaged few TLC555 (cmos version of 555) from dumpster drivings while ago, mostly people throw them away in bulk.

Actually what I love to salvage is the BNC connectors, the older ones are quite good, all brass with thick nickel plating construction. 

Something look like this

I actually use on like this in my printer Had to buy it because the new PC didn't have LPT anymore, and my LaserJet 4000 is uber-reliable and uber-economic workhorse (despite being a 20kg 40x40x40cm).

[dfmischler]

Many years ago I repaired a friend's electronic dog collar that used a 556 to drive the transistor that charged the coil that gave the shock.  That was a very old design, though; it had two boxes on the collar: one for the radio and "shocker" and another for the Ni-Cd battery.  I think it was a Dog Radartron 300DT.

[magetoo]

IIRC, the Commodore 64 had one for debouncing the RESTORE key.

That particular key was hardwired to the NMI line; I guess having bursts of unmaskable interrupts while the key settled would be bad.  You also often had to hit the RESTORE key pretty hard before it did anything, no idea if this was the reason.

They get used in cheap PC motherboards some times to drive the motherboard speaker. Other times they use a piezo, or on higher end boards they'll use a more advanced audio chip.

Are you sure?  I thought this function was integrated in the chipsets everyone use.  (Or is it considered "legacy hardware" nowadays and has been dropped?)