555 timer design contest

The 555 Timer IC is an integrated circuit (chip) implementing a variety of timer and multivibrator applications introduced in 1971. The 555 part is still in wide use, thanks to its ease of use, low price and good stability.

555 Contest claims to be biggest, newest, most-independently conceived 555 timer design contest the world has ever seen! The organizers of the contest are interest in seeing new designs and creativity blossom. Now it is time to act because all entries must be submitted by March 1st, 2011. Yeah, it’s quick, but the world moves fast. And remember that “You’ve got 8 pins…and one shot.” So visit http://www.555contest.com/ for more details.



  1. 555 AM radio « Tomi Engdahl’s ePanorama blog says:

    [...] AM radio I have earlier written about 555 timer design contest. The contest is over and winning circuits have been found. Here is one very interesting contest [...]

  2. Wanda Bean says:

    Logo design contests have grown into one of the most feasible ways for companies to have their brand identities designed at an affordable price range while at the same time also getting high quality, creative concepts. Those who participate in these projects find it to be a great platform for them to display their skills and also earn a good amount of money by winning. Though all this sounds pretty easy, there are certain issues that you must be aware of. Take a look at some of the guidelines below and increase your chances of winning a logo design contest.

  3. Tomi Engdahl says:

    Hans Camenzind remembered

    Hans Camenzind, the Swiss emigre analog guru who invented one of the most successful circuits in electronics history and introduced the concept of phase-locked loop to IC design, passed away in his sleep at the age of 78 on August 15, 2012.

    During his career at four different companies he designed the first integrated class D amplifier, introduced the phase-locked loop concept to ICs, invented the semi-custom IC and created the 555 timer. He had designed 151 standard and custom ICs.

    Hans also wrote books: “Much Ado About Almost Nothing”, A history of electricity and electronics and “Desigining Analog Chips”

  4. Tomi Engdahl says:

    Atari punk stick puts a synth in a joystick

    The Atari Punk Console, a tiny synthesizer based on the ubiquitous 555 timer chip, is the first build de rigueur for any budding electronic wizard wanting to build musical devices. With just a handful of caps, resistors, and a pair of pots, the APC is a fabulously fun and easy build made even cooler by [Pat]‘s addition of a joystick.

    Atari Punk Stick

  5. Open 7400 Logic Competition « Tomi Engdahl’s ePanorama blog says:

    [...] If you found this Open 7400 Logic Competition interesting, you might also want to check my posting on 555 timer design contest. [...]

  6. free samples says:

    Some truly interesting details you have written.Aided me a lot, just what I was searching for :D.

  7. Tomi Engdahl says:


    Eric Schlaepfer built a discrete, working NE555 timer to honor Hans Camenzind in the style of one of Jim Williams’ analog electronics art projects

  8. Tomi Engdahl says:


    A working 555 timer electronic piece of art (In the style of Jim Williams) by Eric Schlaepfer atop a giant 555 timer in memory of Hans Camenzind

  9. ministeredelecologiededroite.fr says:

    Good site you’ve got here.. It’s difficult to find high-quality writing like yours nowadays.

    I truly appreciate people like you! Take care!!

  10. Tomi Engdahl says:

    What’s inside a 555?

    The 555 timer chip is a ubiquitous piece of technology that is oft-considered the hardcore way of doing things. Of course, the old timers out there will remind us that discrete transistors are the badass way of doing things, and tubes even more so. It’s not quite at the level of triodes and transformers, but Evil Mad Scientist’s discrete 555 kit is still an amazing piece of kit.

    Instead of transistors and resistors etched into silicon as in the OG 555, [Windell] over at EMS turned the basic circuit inside a 555 into a mega-sized version using discrete components.

  11. Tomi Engdahl says:

    The “Three Fives” Discrete 555 Timer Kit

    We’re pleased to announce our newest kit, the “Three Fives” Kit, a kit to build your own 555 timer circuit out of discrete components. Here’s a way to re-create one of the most classic, popular, and all-around useful chips of all time.

    The kit is a faithful and functional transistor-scale replica of the classic NE555 timer integrated circuit, one of the most classic, popular, and all-around useful chips of all time.

    adapted from the equivalent schematic in the original datasheets for the device

    The kit is designed to resemble an (overgrown) integrated circuit, based around an extra-thick matte-finish printed circuit board.

    To actually hook up to the giant 555, there are the usual solder connection points, but there are also thumbscrew terminal posts that you can use with bare wires, solder lugs, or alligator clips.

    you can actually hook up probes and monitor what happens at different places inside the circuit.

  12. Tomi Engdahl says:

    A 555-Based, Two-Channel Remote Control Circuit

    The great thing about this circuit is its simplicity. It’s often so easy to throw a microcontroller into the mix, that we forget how effective a setup like this can be. It could also be a great starter circuit for a kid’s workshop, demonstrating basic circuits, timers, and even a NOT gate.

  13. Tomi Engdahl says:

    555 based AM radio transmitter

    Bust out that 555 timer and use it to build your own AM radio transmitter.

  14. Tomi Engdahl says:

    Surface-mount 555 PWM circuit

    I wanted to dim my room LED lighting with a potentiometer, and decided on creating a solution from scratch to make it more fun and educative. I decided to go with the fairly well-known 555 PWM circuit. To decrease size and for learning purposes I decided on using surface-mount components for the first time. The reason I wanted to make this 555 PWM circuit is actually just to see if I could solder SMD components on home-etched PCB’s, and to see how hard it actually is.

    This was very fun for a first etching and SMD-soldering project, but there are plenty of improvements to be made.

  15. Tomi Engdahl says:

    Mega-Cool Transistor-Level Classic Chip Kits

    I was just meandering my way around the Adafruit.com website — as you do — when I ran across something that made me gasp with awe and admiration (I’m just thankful I didn’t squeal with delight).

    This is such a cool idea — it’s a XL741 Discrete Op-Amp Kit from those little scamps at the Evil Mad Scientist Labs. As it says on the Adafruit website: “This is a faithful and functional transistor-scale replica of the µA741 op-amp integrated circuit, the classic and ubiquitous analog workhorse.”

    But wait, there’s more, because I then ran across this Discrete 555 Timer Kit, which also comes from the little rapscallions at the Evil Mad Scientist Labs. In this case, we’re talking about a functional transistor-scale replica of the classic NE555 timer integrated circuit, which the Adafruit website correctly describes as “One of the most classic, popular, and all-around useful chips of all time.”

  16. Tomi Engdahl says:

    555 Teardown and Analysis

    If you are even remotely interested in electronics, chances are the number ‘555’ is immediately recognizable. It is, after all, one of the most popular IC’s ever built, with billions of units sold to date. Designed way back in 1970 by Hans Camenzind, it is still widely available and frequently used for various applications. [Ken Shirriff] does a teardown and analysis of a 555 and gives us a look at the internal structure of this oldie.

    555 timer teardown: inside the world’s most popular IC

  17. Tomi Engdahl says:

    Celebrating Hans Camenzind’s other achievements

    On this fourth anniversary of Hans Camenzind’s passing on August 15, 2012, I wanted to highlight some of the other technical achievements he had besides the ubiquitous 555 timer.

    Camenzind’s paper for the IEEE Journal of Solid-State Circuits in December 1978, entitled A Low Voltage IC Timer, co-authored by Richard Kash. Kash joined Fairchild after he got his BSEE in 1976 and later joined Interdesign in 1977. By the time that this paper was presented in 1978, Camenzind had founded Interdesign in 1970 to further his revolutionary ideas for IC design and was President there until 1977 when he founded Tridar to develop a phone that would function as a handheld phone and a speakerphone. Unfortunately, this company did not succeed.

    In this design, Camenzind used a neat sensing circuit to achieve the lower threshold and demonstrated that the 555 could function with a supply voltage of under 1 volt with good precision.

    It’s all about the current source design. In n-p-n diode-based current sources like in his original design and other existing IC designs at that time, designers needed to keep the transistors out of saturation so as to not steal current from the other current sources in the architecture of the current source design. Camenzind fashioned a saturation detector from n-p-n transistors because lateral p-n-p transistors would not function properly in sensing a saturation occurance.

    Back in 1966, ten years after the first issue of EDN, Camenzind determined that pulse width modulation (PWM) had great potential advantages in ICs, especially in a conventional audio amplifier which, at that time, was not really suitable for an IC design because of poor efficiency and high power

    Camenzind mentions that the maximum theoretical efficiency of a class B amplifier was 78 percent and, in practical circuits, it was difficult to reach an efficiency of more than 60 %. For

    Integrated class A and B amplifiers would not follow the trend of decreasing costs of that time.

    Camenzind showed in breadboarded models, using complementary transistors, an efficiency of 89 % was reached at 1W

  18. Tomi Engdahl says:

    Building a computer out of 555 chips

    [M. Eric Carr] started off implementing Boolean logic with a 555. After building a universal gate, he moved onto putting one bit of memory in a single 555. This design uses the 555 as a latch and is one of the craziest off-spec uses of a 555.

  19. Tomi Engdahl says:

    What’s All This 555 Timer Stuff, Anyway?

    Back in 2011, Jeff Hamilton contacted Bob Pease, asking for Bob’s experience with the classic 555 timer IC.

    Pease replied in his characteristically straightforward way. He noted:

    “Hi, Jeff H., I have almost never used a 555. Maybe never? I use op-amps, LM324′s, LM311′s, LF356′s. I use 74HC04′s and 74C14′s but not 555′s. I’ve used ECL fast logic, and discrete transistors. But the 555 just does not do anything precise, or even semi-precise, that I need done. So that’s one thing I can “share” – my favorite circuit to use a 555, is: a blank piece of paper. Never touch the things. Go ahead and print that. / rap”

    I agree with Pease, and have always regarded the 555 timer as more of a hobbyist IC. By that I mean it can get you in trouble in any volume application where repeatability and consistent performance is critical. Pease’s comment about the 555 not being precise is true.

    Furthermore, maybe you designed in the knock-off CMOS version, and the purchasing agent decided to be a hero and substitute some third-world-sourced, original bipolar part. After all, both parts have 555 in the part number, so they both must work, right?

    Other problems I have had with 555s involve their power-supply sensitivity.

    Then there are the problems we create with the components in our 555 circuits. If you use high-value resistors, you start to get problems with leakage.

    If you use large-value polarized capacitors, well, they not only have high leakage, but they are also very poor in reliability. Ceramic capacitors are microphonic; they will change the circuit frequency when you tap on them. The acoustic nature works both ways—the ceramics will emit sound if the circuit frequency is in the audio range.

    Thankfully, just like Maxim solved your power-on reset problems, Linear Technology has solved your 555 timing problems with its line of TimerBlox chips.


  20. Tomi Engdahl says:

    You Know You Can Do That with a 555

    Hardly a week goes by that we don’t post a project where at least one commenter will lament that the hacker could have just used a 555. [Peter Monta] clearly gets that point of view. For a 555 design contest, he created both digital logic gates and an op amp, all using 555 chips. We can’t quite imagine the post apocalyptic world where the only surviving electronic components are 555 chips, but if that day were to come, [Peter] is your guy.

    Using the internal structure of the 555, [Peter] formed a basic logic gate, an inverter, latches, and more. He also composed things like counters and seven-segment decoders. He had a very simple 4-bit CPU design in Verilog that he was going to attempt until he realized it would map into almost 400 chips (half of that if you’d use a dual 555, but still)

    An op-amp made from 555 chips

  21. Tomi Engdahl says:

    Learning The 555 From The Inside

    One way to understand how the 555 timer works and how to use it is by learning what the pins mean and what to connect to them. A far more enjoyable, and arguably a more useful way to learn is by looking at what’s going on inside during each of its modes of operation. [Dejan Nedelkovski] has put together just such a video where he walks through how the 555 timer IC works from the inside.

    We especially like how he immediately removes the fear factor by first showing a schematic with all the individual components but then grouping them into what they make up: two comparators, a voltage divider, a flip-flop, a discharge transistor, and an output stage.


  22. Tomi Engdahl says:

    EEVblog #555 – 555 Timer Kit

    Dave celebrates the classic 555 timer IC by building the Evil Mad Scientist “three fives” discrete timer kit.

  23. Tomi Engdahl says:

    Ode to a 555 Timer

    When you are an electronics engineer, some numbers cry out to you when you hear them, like 4004 (the world’s first commercial microprocessor chip) and 8051 (if not the first, then certainly one of the most beloved of the early microcontrollers).

    And, of course, one number that makes all of our ears prick up is 555. This was the number assigned to the Signetics Timer integrated circuit (IC), which was designed by Hans R. Camenzind in 1971 and released to the market in 1972. Comprising 25 transistors, two diodes, and 15 resistors and utilizing some clever design techniques — such as replacing an external constant-current source with a direct internal resistance — Hans managed to squeeze the 555 into an eight-pin package.

    The 555 has three main operating modes: monostable (one-shot), bistable (Schmitt trigger), and astable (free-running). The versatility of the 555 — coupled with its low price, ease of use, and stability — means that the 555 is still in use to this day.

  24. Tomi Engdahl says:

    555 Timer – Types, Construction, Working & Application – Block & Circuit

  25. Tomi Engdahl says:

    Making The World’s Fastest 555 Timer, Or Using A Modern IC Version

    If you’re not familiar with the 555 timer, suffice it to say that this versatile integrated circuit is probably the most successful ever designed, and has been used in countless designs, many of which fall very far afield from the original intent. From its introduction, the legendary 555 has found favor both with professional designers and hobbyists, and continues to be used in designs from both camps. New versions of the IC are still being cranked out, and discrete versions are built for fun, a temptation I just couldn’t resist after starting this article.

    The first 555 timers, the NE555V/SE555T from Signetics, were produced more than 47 years ago. Designed by Hans Camenzind

    Signetics chose not to patent the design.

    The Art of Electronics called the 555 a kit of parts, and that’s probably the best overall description you can come up with.

    What can you do with these parts? Perhaps the most common use is as an astable multivibrator or RC relaxation oscillator.

    The 555 isn’t just an oscillator, though. It can also be used in monostable (one-shot) mode, producing a fixed output pulse width in response to a low-going signal on the TRIGger input.

    Just because it’s so often used does not mean that the 555 is universally loved. An EDN column from 2011 shares some hard-earned lessons in 555 failures and the fact that an analog legend, Bob Pease, was not at all a fan of the part. Still, it’s cheap, easy to use, and good enough for many, many applications.

    Why Not a Microcontroller?

    Given its versatility, there’s little surprise that this IC continues to find use. But, in the age of $0.03 microcontrollers, one has to wonder if the 555 will eventually lose ground. Besides the amazing variety of innovative designs, and hacks, to build on, there are still plenty of reasons to choose this part over a microcontroller solution, including:

    No programming required
    No software bugs
    No NRE (non-recurring engineering) costs for programming and debugging
    No manufacturing time loading code
    Wide supply voltage range
    No flash memory bitrot or soft errors from cosmic rays or voltage spikes
    No hung or stuck software states; no watchdog required

    So, once we’ve decided to go with a 555-type circuit, it’s time to have a look around and see what’s available in 2019.

    TI’s LMC555 claims to be the smallest and fastest fully-featured 555 available. This is a CMOS variant, with a maximum frequency of 3 MHz according to the datasheet.

    Microchip offers its own version of the 555 concept with the MIC1555/57 timers, both in small but relatively hacker-friendly SOT23-5 packages.

    Roll Your Own

    a 555 built from discrete transistors took one of the prizes in the famed 555 Contest

    I went for raw speed, choosing a pair of fast ADCMP600 comparators and a latch made from a 74LVC2G02 dual NOR gate. The comparators have a propagation delay of only 3.5 ns, with the NOR gates typically under 2 ns

  26. Tomi Engdahl says:

    The Three Faces Of The 555

    In these days of cheap microcontrollers, it is hard to remember there was a time when timing things took real circuitry. Even today, for some applications it is hard to beat the ubiquitous 555 timer IC.

    has a video showing the three major modes you typically see with the 555: astable, bistable, and monostable.

    555 Timer All Modes


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