Where have you actually come across a 555 timer in the wild? - Page 1
Forum section: electronics / general

author: thomastheo
author_rank: Regular Contributor
timestamp: March 31, 2014, 02:25:14 pm
content: 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...

author: Jarrod Roberson
author_rank: Regular Contributor
timestamp: March 31, 2014, 02:30:11 pm
content: 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.

author: kayvee
author_rank: Regular Contributor
timestamp: March 31, 2014, 02:32:59 pm
content: Burglar alarm siren driver was a popular application.

author: poorchava
author_rank: Super Contributor
timestamp: March 31, 2014, 02:36:07 pm
content: 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.

author: BillyD
author_rank: Regular Contributor
timestamp: March 31, 2014, 02:39:59 pm
content: 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.

author: Stonent
author_rank: Super Contributor
timestamp: March 31, 2014, 02:40:50 pm
content: I've heard that a lot of hard drives have a 555 somewhere for driving the motor.

author: mariush
author_rank: Super Contributor
timestamp: March 31, 2014, 02:54:11 pm
content: 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).

author: nessatse
author_rank: Regular Contributor
timestamp: March 31, 2014, 02:59:34 pm
content: 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

author: tom66
author_rank: Super Contributor
timestamp: March 31, 2014, 03:19:52 pm
content: 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...

author: thomastheo
author_rank: Regular Contributor
timestamp: March 31, 2014, 03:32:10 pm
content: 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.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 31, 2014, 03:36:52 pm
content: 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

author: BravoV
author_rank: Super Contributor
timestamp: March 31, 2014, 03:50:38 pm
content: 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

author: Jarrod Roberson
author_rank: Regular Contributor
timestamp: March 31, 2014, 03:50:56 pm
content: 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.

author: Biff383
author_rank: Regular Contributor
timestamp: March 31, 2014, 03:55:25 pm
content: Yes.....bike horn.....actually a 556 I think (2 in one). I got a bunch for free.

author: thomastheo
author_rank: Regular Contributor
timestamp: March 31, 2014, 03:56:32 pm
content: Quote from: Jarrod Roberson on March 31, 2014, 03:50:56 pmJust checked to see if my boss flanger has one... and alas, no dice )

author: PedroDaGr8
author_rank: Super Contributor
timestamp: March 31, 2014, 11:39:58 pm
content: A variety of instruments at work use them in the power supplies (old Amersham Biosciences AKTA FPLC, Gilson Fraction collectors etc.)

author: David_AVD
author_rank: Super Contributor
timestamp: March 31, 2014, 11:42:13 pm
content: 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.

author: Fraser
author_rank: Super Contributor
timestamp: March 31, 2014, 11:55:55 pm
content: 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'

author: Phaedrus
author_rank: Frequent Contributor
timestamp: April 01, 2014, 12:27:19 am
content: 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.

author: Rerouter
author_rank: Super Contributor
timestamp: April 01, 2014, 02:01:34 am
content: 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)

author: deth502
author_rank: Frequent Contributor
timestamp: April 01, 2014, 02:06:16 am
content: the device we use at work to check the depths of our test wells has one in it.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 01, 2014, 02:24:10 am
content: 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.

author: poorchava
author_rank: Super Contributor
timestamp: April 01, 2014, 07:57:56 am
content: Quote from: BravoV on March 31, 2014, 03:50:38 pmI actually use on like this in my printerHad 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).

author: dfmischler
author_rank: Frequent Contributor
timestamp: April 01, 2014, 12:16:29 pm
content: 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.

author: magetoo
author_rank: Frequent Contributor
timestamp: April 01, 2014, 12:44:30 pm
content: 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.Quote from: Phaedrus on April 01, 2014, 12:27:19 amAre you sure? I thought this function was integrated in the chipsets everyone use. (Or is it considered "legacy hardware" nowadays and has been dropped?)

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 01, 2014, 12:58:20 pm
content: For sure, there's no reason for a 555 as a timer... perhaps it was just being used as a schmitt trigger buffer/driver?Tim

author: magetoo
author_rank: Frequent Contributor
timestamp: April 01, 2014, 03:20:50 pm
content: Maybe "debounce" wasn't exactly correct.. My guess is it was there to guarantee a minimum on time so that the CPU would have time to deal with the interrupt before the next could come in.

author: Phaedrus
author_rank: Frequent Contributor
timestamp: April 01, 2014, 04:01:38 pm
content: Quote from: magetoo on April 01, 2014, 12:44:30 pmI haven't seen it in a while, so I guess it's deprecated. But I remember seeing it on an old Asus AMD board, socket 939. And I thought I've seen them on a few other motherboards as well.

author: G7PSK
author_rank: Super Contributor
timestamp: April 01, 2014, 05:11:28 pm
content: The first MIG welder I bought had two 555 chips, one to time the post flow and one for the wire feed motor burn back and stitch weld. I still have the circuit diagram somewhere.

author: thomastheo
author_rank: Regular Contributor
timestamp: April 01, 2014, 05:29:06 pm
content: Quote from: mojo-chan on April 01, 2014, 03:30:20 pmThat's quite elegant, and reliable to boot.

author: mc
author_rank: Regular Contributor
timestamp: April 01, 2014, 06:00:40 pm
content: In a 24 to 12volt dropper for trailer electrics on a lorry. Quite an over-engineered solution, but I'm guessing they just keep using an old design rather than redesign it.

author: TheWelly888
author_rank: Frequent Contributor
timestamp: April 01, 2014, 06:46:41 pm
content: I've seen medical equipment that uses those 555 and 556s ICs for basic square wave generation.

author: fcb
author_rank: Super Contributor
timestamp: April 01, 2014, 06:56:02 pm
content: I designed one into a product last month. It generates ~96KHz to bootstrap an isolated supply (until the system is booted and can generate precision 96KHz).

author: Kryoclasm
author_rank: Regular Contributor
timestamp: April 01, 2014, 07:19:56 pm
content: Recently in a rooftop flashing beacon.

author: Neilm
author_rank: Super Contributor
timestamp: April 01, 2014, 08:09:37 pm
content: I had to make a small plug in device to allow the product I had designed to be run under computer control. I put a 555 in it to generate a square wave - see pin toggle real device present.

author: david77
author_rank: Frequent Contributor
timestamp: April 01, 2014, 08:11:58 pm
content: In my 20 EUR cheapie toaster, used as timer for the bread ejector thingie. With the obligatory knob on the side to choose how burnt you'd like your bread.I've used it and will continue using it myself for all kinds of things, but you can hardly call what I do "production".

author: steve30
author_rank: Frequent Contributor
timestamp: April 01, 2014, 09:02:09 pm
content: They are used in some 68000 based computers in the reset circuit (including the Amiga 500+). Can't remember exactly what it does though. We had an educational 68k board at college, and the documentation explained its purpose, but I forget.They are quite old designs though. I very rarely see 555 chips in use in products. Or at least not ones that are marked with '555'.

author: lapm
author_rank: Frequent Contributor
timestamp: April 01, 2014, 09:17:42 pm
content: Last time i run into one on wild was one of those orange road flashes. The 555 was running flashlight bulb throw transistor.. Transistor had died, so needed replacement.. Was beyond me why friend of mine wanted it fixed instead of buying new one...Something like this one:http://thumbs3.ebaystatic.com/d/l225/m/mM8ExgkRmnUqsEXf0TITuUg.jpg

author: magetoo
author_rank: Frequent Contributor
timestamp: April 01, 2014, 10:02:11 pm
content: Quote from: Phaedrus on April 01, 2014, 04:01:38 pmI meant the other way around, older machines will have something that is compatible to an actual 82xx (or whatever the number was) timer chip, not a 555, and probably needs that compatibility to be able to run DOS or something.So I imagine slightly newer systems that don't need the compatibility could have dropped it and used something else for a beeper instead, like the 555 triggered by a GPIO. (And anything recent would get rid of the internal speaker altogether. Or use a "real" audio chip?)Historic note: In the original PC, the timer chip had three separate timers - it generated a periodic interrupt at 18.2 Hz for DOS, drove the speaker with another timer, and also did a third thing I can't remember.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 01, 2014, 10:37:03 pm
content: Quote from: magetoo on April 01, 2014, 10:02:11 pmThird is actually the first (timer 0): interrupt for the DMA controller to perform another DRAM refresh. Every couple of microseconds I think.The 18.2Hz is used by the clock (at least when DOS is handling it, I think?). You can hijack the interrupt and use the count for something else (say, an in-game timer to trigger another frame of activity), but don't be surprised if your system time is running slow afterwards.This, by the way, is precisely why, if a motherboard had a 555, it's not used to generate PC tones: the timer has a pin toggle mode which does it directly. Give or take a driver for the PC speaker (2" 8 ohm in the old fashioned models, usually some piss tiny piezo these days).All this stuff was integrated first into a SuperIO chip (along with all the other system functions, and serial and parallel), then into the South Bridge when that become a thing. If your motherboard has a BIOS, it has all of this stuff in it somewhere; UEFI models may not, I don't know.Tim

author: Jarrod Roberson
author_rank: Regular Contributor
timestamp: April 09, 2014, 07:18:49 pm
content: Ben Heck finds a 555 timer chip in SOT packaging no less in a drill trigger assembly!http://youtu.be/PUZyzU24Ta4?t=3m53s

author: peter.mitchell
author_rank: Super Contributor
timestamp: April 13, 2014, 04:43:19 am
content: I've seen a few of them on power supplies for fan failure. The RPM line from the fan triggers it a minimum number of times a second.

author: kolbep
author_rank: Frequent Contributor
timestamp: April 13, 2014, 05:12:50 am
content: Saw a 556 in a Barcode Scanner that they use at the Supermarket tills...

author: Anks
author_rank: Frequent Contributor
timestamp: April 13, 2014, 05:16:08 pm
content: Quote from: David_AVD on March 31, 2014, 11:42:13 pmCrown amplifiers that use the VZ supply (variable impedance) Macrotech 5000VZ and 3600VZ are the most popular. Its very clever in that its quickly switches voltage dependent on the needed output so the transistors don't have to dissipate the extra unneeded energy as heat.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 14, 2014, 03:07:19 am
content: Quote from: Anks on April 13, 2014, 05:16:08 pmSome modern digital amplifiers also vary the supply voltage depending on the volume setting. Apart from the efficiency improvement, it makes it easier to get good resolution at low volume settings. Some others have multiple fixed voltage rails and are basically multi level inverters.

author: kolbep
author_rank: Frequent Contributor
timestamp: April 14, 2014, 01:12:29 pm
content: Took a lot of searching, but I just found one in the wild....

author: madires
author_rank: Super Contributor
timestamp: April 14, 2014, 01:30:19 pm
content: Quote from: kolbep on April 14, 2014, 01:12:29 pmI hope that wild electronics bug didn't bit you.

author: kolbep
author_rank: Frequent Contributor
timestamp: April 14, 2014, 01:54:11 pm
content: Now just to track down a resistor colony, and I should be well on my way....

author: SeanB
author_rank: Super Contributor
timestamp: April 14, 2014, 06:14:58 pm
content: Time to mow your lawn, all the rain is getting it growing nicely.

author: fcb
author_rank: Super Contributor
timestamp: April 15, 2014, 01:38:41 pm
content: I once found one buried in the carpet. It left 8 little holes in my foot.

author: ErikTheNorwegian
author_rank: Frequent Contributor
timestamp: April 15, 2014, 01:56:59 pm
content: A wild 555 cought by the cat, right before it was to eascape out the window... and into the wild!

author: amyk
author_rank: Super Contributor
timestamp: April 15, 2014, 01:58:24 pm
content: Quote from: T3sl4co1l on April 01, 2014, 10:37:03 pmIf you saw a 555 on a mobo, chances are that it's some other 8-pin IC with that marking code and not the timer. Ever since the first PC, its main timer is an Intel 8254 or compatible. There have been other ones introduced later but the 8254 should still be there, integrated into the chipset. Even Apple's computers now have one, ever since they switched to being (almost) PC-compatible.

author: kx5
author_rank: Newbie
timestamp: April 15, 2014, 03:41:48 pm
content: Quote from: kolbep on April 14, 2014, 01:12:29 pmMaximius Cmosinellidae?

author: ignator
author_rank: Regular Contributor
timestamp: April 15, 2014, 03:50:38 pm
content: I saw one used in a timer for spraying from an aerosol can for room freshening. I think it was Glade brand.

author: lemmegraphdat
author_rank: Frequent Contributor
timestamp: April 16, 2014, 01:23:20 am
content: Product detect simulator for diagnosing and repair of ridiculously expensive date code printer. Sends a 4v pulse to the printer to fire the print head. The Pointy Hair wired the connectors wrong and blew the chips. Took them home and repaired from parts in my junk box.

author: dexters_lab
author_rank: Unknown
timestamp: July 25, 2016, 01:09:07 pm
content: spotted this today and remembered this threadNEC C1555 variant of the 555 in this 8" floppy disk drive dated 1984.

author: bitslice
author_rank: Frequent Contributor
timestamp: July 25, 2016, 01:16:48 pm
content: NASA uses them for jet engine controlhttp://www.techbriefs.com/component/content/article/ntb/tech-briefs/physical-sciences/5398actually I searched for that just as a joke, joke's on me...

author: Synthetase
author_rank: Regular Contributor
timestamp: July 25, 2016, 04:28:22 pm
content: Used to find them in old joysticks. The stick moves a linear pot, changing the pulse freq of the 555.I've also seen them in electric fence controllers for pulse generation.

author: German_EE
author_rank: Super Contributor
timestamp: July 25, 2016, 05:01:13 pm
content: The 'bonnggg' sound on Kone Elevators as the doors open and close is generated by a 555 on the control PCB.

author: Gyro
author_rank: Super Contributor
timestamp: July 25, 2016, 06:06:08 pm
content: Fan speed controller in Instek bench PSUs.P.S. I think it still gets 'typecast' as a timer, whereas a couple of voltage comparators with tweakable threshold resistor chain, a resetable flipflop and a strong push pull output stage in a single package is a gift for a cunning low cost designer.

author: CJay
author_rank: Super Contributor
timestamp: July 25, 2016, 08:08:15 pm
content: They're used in some of the HP Storage array cache battery charge controllers.

author: RobK_NL
author_rank: Frequent Contributor
timestamp: July 25, 2016, 08:17:58 pm
content: In the PSU of a Keithley 2001

author: tautech
author_rank: Super Contributor
timestamp: July 25, 2016, 08:23:26 pm
content: Nobody's mentioned kitchen toasters.

author: Rolo
author_rank: Regular Contributor
timestamp: July 25, 2016, 08:38:03 pm
content: In my Philips outdoor lamp with dusk sensor.

author: Brumby
author_rank: Unknown
timestamp: July 26, 2016, 01:00:44 am
content: Quote from: tautech on July 25, 2016, 08:23:26 pmYes they have...Quote from: david77 on April 01, 2014, 08:11:58 pm

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 26, 2016, 01:50:56 am
content: I once took apart a microwave that used a UJT (Uni-Junction Transistor). I think I've got you beat on thatTim

author: Cubdriver
author_rank: Unknown
timestamp: July 26, 2016, 03:17:25 am
content: They were used as watchdog timers in the microwave generators a company I used to work for made for a piece of semiconductor processing equipment.-Pat

author: Enigma-man
author_rank: Regular Contributor
timestamp: July 26, 2016, 03:19:02 am
content: I saw a 555 used in a super simple switchmode step-up converter to power Nixie tubes. Nine volts in, 170V out.Comes in kit form with PC board and parts. After doing a search for "nixie tube power supply" it showed upin one of the images. I suppose one could buy it today if one were looking for such a thing.http://www.ledsales.com.auThe attached image is not mine

author: Stray Electron
author_rank: Super Contributor
timestamp: August 05, 2016, 11:22:27 pm
content: Quote from: thomastheo on March 31, 2014, 02:25:14 pmBack in the late 70s I worked for a major US food processing company. We used packaging machines that were made by Triangle Packaging Machine Corp in Chicago. All of the timing in them was done via 555s. There were a couple of dozen in there. This machine took a roll of plastic film and formed the bags like you get frozen vegetables in. It formed rolls of plastic sheeting into the tubes, heat sealed the side seam, filled them from one of four hoppers, pulled them down and heat sealed the tops and cut them off of the roll and formed and heat sealed the bottom of the next bag. The entire process took about 3 seconds and every operation was timed by a 555 circuit and each timer triggered the succeeding ones. It actually worked pretty well but if something went wrong everything that followed it went wrong and things could get "interesting" real fast!Some of the old HP gear used 555s to drive a switcher type power supply. IIRC I've seen them in some of the HP-IB disk drives and, I think, in one of the old HP desktop calculators.

author: setq
author_rank: Frequent Contributor
timestamp: August 05, 2016, 11:36:13 pm
content: I've seen a 555, 311, BD13x based naive boost converter in what appears to have been a display driver for a VFD (it was skip dived). Looked 1980s vintage so might have been cheaper than a dedicated IC at the time. The display was smashed but was quite large. I built a replica of it a few months ago replacing the BD transistor with an IRF510 as it looked interesting and it's possible to get a good 500mA at 30v out of the circuit with some tweaks without anything exploding. Didn't measure the efficiency however. Picture below - no schematic I didn't bother:555 on left running at ~50khz. Voltage ref at top. LM311 comparator in middle. IRF510 top right with inductor. Voltage divider at bottom. If the voltage gets too high it turns the oscillator off - dumb as chips.

author: MadTux
author_rank: Frequent Contributor
timestamp: August 05, 2016, 11:45:31 pm
content: HP 8662/8663A SMPS controller also has an NE555 in it.Found it a bit weird, cheap NE555 in a 40 or 75k$ signal generator

author: timb
author_rank: Super Contributor
timestamp: August 05, 2016, 11:52:25 pm
content: Quote from: Synthetase on July 25, 2016, 04:28:22 pmYeah, surprised this wasn't mentioned sooner. I think Woz pioneered this method with the Apple II joysticks. If I remember correctly, it was a 556 and the joystick was actually two potentiometers. The CPU would time the incoming pulses to determine position.A very elegant solution!

author: Enigma-man
author_rank: Regular Contributor
timestamp: August 06, 2016, 02:06:25 am
content: Here's my very recently constructed 555 based Nixie power supply to run some 1.5" Beckman 7 segment displays as may have been seen inanother thread.

author: whitevamp
author_rank: Regular Contributor
timestamp: August 06, 2016, 03:57:17 am
content: just yesterday i had opened up a Jensen 3022 LX car stereo amp, im guessing circa late 80's - 90's. and found this little gem in there. a ne555.http://elektrotanya.com/jensen_xa_3022_lx_sch.pdf/download.htmlhttps://docs.google.com/document/d/1sA30dH34P9BgDo_b-63wjXetkeeazWKl5QKfJTQ5ELg/edit

author: jh15
author_rank: Frequent Contributor
timestamp: August 06, 2016, 04:10:48 am
content: I always liked to play with unijunction transistors in 1971. Then the 555 came out and that was more fun. Paid for some samples from an engineer I worked with in a Bell System OEM plant. (I think he got them for free but sold them to me for 4.00 I didn't care.) plus some early PLL chips.uni's were used in the Bell MagiCall dialers, and I always went or got floor sweepings, don't think dumpsters were around then.Built a phone answerer out of a 555 and a pll, and 2 cassette recorders, think it was a Radio Electronics magazine plan.I repaired avionics instruments, and believe it was the Boeing 747 air speed indicator that had a flatpack 555 in it, not sure if it was the same instrument that had a uni. They never went bad. In fact the designs seemed so weird to some.In my opinion, they were designed to minimize the use of large value capacitors like tantalums and aluminum electrolytics for reliability.Jokes went around when I got a Quad AC ammeter from US 1 aircraft to fix. It had a sticky analog display needle written on the repair request. Jokes went around if then pres Clinton had found another intern, etc.

author: dastructhm
author_rank: Contributor
timestamp: October 09, 2022, 02:06:48 am
content: I've torn down many electronic products. I've never seen a 555 timer inside.

author: AVGresponding
author_rank: Super Contributor
timestamp: October 09, 2022, 09:14:57 am
content: Quote from: dastructhm on October 09, 2022, 02:06:48 amHere's one for you then:LED fire alarm beacon, manufacturing date 22/07. The design probably hasn't changed much if at all since then, as the LPCB certification process costs money.