555 timer output hight and low? Answered

I just soldered up a 555 monostable circuit following an internet tutorial and for some reason the output seems to be both low and high. it can power a LED connected to the 0V & pin 3 and the 9V & pin 3. any ideas what might have happened?

Asked by DrVonTrap 7 years ago


Simple 12v battery level LED indicator w/ A single 555 IC, none on the net. (555 is for looks) is it possible?

Well im somewhat novice and I was wanting to make a circuit to monitor the level of a 12v car battery with 3 LEDS (although more is cool) Yellow for low, Green for good and red for overcharge. Ive looked all over and cannot find a circuit that uses a single 555 ic to do this easy task.

Asked by Sky Graham 6 years ago


Adding Keywords

Please advise on how to add an additional keyword to a published Instructable.  I have tried adding the keyword "555" or "555Timer" to my recently published Instructable "Electronic Paperweight" but keep getting an error message.  Editing the Instructable is no problem, but cannot add a new keyword.

Posted by TinkerJim 6 years ago


555 timeout troubles?

Evening all,  This is most likely a very basic problem but for the life of me I can't find the solution. The project: auto folding wing mirrors (see below) http://www.lexusownersclub.co.uk/forum/index.php?app=core&module=attach&section=attach&attach_id=6108 The problem: for some reason my alarm logic is the opposite way round, most likely due to the removal of my motion sensor due to it tripping my alarm when locked. Now I have modified the circuit shown in the PDF to remove TR2 and R4 so the I/P to the 555 is kept high by the 12v alarm signal. I have a pot between pin 2 and ground so I can adjust the pull down point as the alarm signal only drops to 9.7V and, obviously, the 555 needs logic high or low. So, having adjusted the pull down point, I find that the 5 second timeout, which worked when I first built the circuit as per the PDF, no longer switches the O/P off.  So so what am I doing wrong or is it just best to us a picaxe to do all of this as I code write up the code in half an hour or so. thanks

Asked by LED Maestro 2 years ago


how are the pins on a ic numbered?

I have been trying to make cylon light bar thing. http://www.evilmadscientist.com/article.php/CylonOLantern but it isn't working, all the wires an connections are done according to what is said and i asked my neighbour to have a look he is a electrician and he was surprised it didn't go as well. its the NE555  i put it togther. looking down on the plastic.     ______ 1-| o  U    |-8 2-|            |-7 3-|            |-6 4-|_____|-5 was that the wrong way? i have seen other circuit diagrams and the pin numbers where not like that. thank you oh and also is some solder non-conductive? and can you burn wires and make them useless? i don't think i could have fried the chip i getting pro at quick soldering.

Asked by Scotty3000 7 years ago


555 timing circuit?

Asked by gadget01 9 years ago


555?

Whats a 555 and how does it work?

Posted by colmon9 11 years ago



555 timers?

I was wondering if there is a difference between a ne555p timer chip and a ne555d timer chip, and if there is then what is it? if there is a difference between them, then where can i buy a ne555p timer in australia? :)

Asked by jcolefran 8 years ago


555 timer

I need help to understand how a 555 timer works, but mostly how I could build one. or if some ones willing to make one for me, i'll buy it, but it needs to have a ways to control it. well talk if your interested. I need it for a gate control for my SCR induction furnes.

Posted by Danielro10 9 years ago


I want to use a 555 timer to be off for 1 minute, give a brief pulse (about 0.5 seconds).

The circuit is to provide a pulse to a 4017B decade counter to count up to 5 minutes

Asked by ralph4ed 3 years ago


I'm trying to use a 555 timer to flash a LED but I want to be able to adjust the speed of the flashing Answered

I'm trying to build a simple circuit using a 555 timer chip Ideally a low power one so I can power it off 2 AAs to flash a LED at a variable speed from rapid flashing to once every few seconds. any help would be appreciated.

Asked by joeAMERICA 8 years ago


i would like to build a small simple synthesizer using 555 chips if possible. any oe haeve ideas or help?

I have a few 555 timers and  have always wanted to build a sythesizer but i just don't know where to start. i have seen the optical theremin and  the 555 metronome. i could add a pot instead of the photo transistor, and maybe connect the out put from the theremin to the metronome  i would like some thing more like this ,http://hackaday.com/2009/08/28/xr-noise-box/ . i would like to kow if it is possible with 555 timers.

Asked by zs 8 years ago


555 working backwards?

Hey, so i wired up my 555, with a trigger button, and because i only had small resistors at the time, I used one to give a really quick period. however when i put in a brand new 800 KOhm resistor (that should have raised the period to 8 seconds) instead of lengthening the period it put a time limit on the trigger. so now i have an output that stays high for a faction of a second and then the chip can't be re-triggered for 8 seconds. i know people don't have an encyclopedic knowledge of 555, but does anyone more experienced have any ideas why this might have happened. thanks in advance.

Asked by DrVonTrap 7 years ago


Is there a way that I could use a 555 chip to give 5 pulses then stop?

Or any other easy way to create a certain number of pulses? The amount of time this happens in doesn't really matter. The o/p of this pulse generator must have enough voltage/ current to power the clock of a 4024 7 bit counter

Asked by hrimiller 5 years ago


Push button to toggle servo direction - monostable 555 circuit? Answered

I would like to build a circuit where I push a button once and a servo moves 180 degrees and stays there.  If I push the button again it should move back to the start position. A switch is good alternative, whichever would be easier. I've been looking at circuits to do with 555 timers and servos and have found these two which seem useful: http://www.555-timer-circuits.com/servo-controller.html http://www.dummies.com/how-to/content/electronics-components-555-timer-chip-in-monostabl.html Is that second circuit what I need?  How would I change the direction of the servo each time it runs? I looked into flip-flops such as the 4013 which came up as a suggestion instead of a 555 but quickly got out of my depth.  I'm happy tinkering around with electronics but unfortunately don't know too much of the theory...

Asked by Sparrowhawk 4 years ago


panic alarm data?

 i request to get data about panic alarm.

Asked by nelson ndegwa 2 years ago


I just bought 7 555ic timers, all of them are faulty?

I bought 7    555ic timer. i tried to blink an led but the output always stays high. when i swapped the 555 by a 556 it then worked. first i thought that my circuit was wrong. i've verified it countless times all seemed to be good but the pin 3 output was always high. when i used the 556 timer with same components it worked. is the 555 timer at fault or i am missing something?

Asked by ARJOON 7 years ago


Hey Guys,I need some help making a project for school

It needs to have at least 1 555 Timer within it. I was thinking of building a jacobs ladder with a 555 timer or if i could get it working perhaps a sonic pulse generator. Want something interesting and that won't take more then 7 weeks to build. Would it be possible to make a Cree Light and mod it to turn off after X amount of time? I'm just struggling to find idea's as our projects must be able to run off a 12V Battery or less and we cannot make anything dangerous. IE Rocket Launch Controller etc.... Thanks

Asked by bcurko 9 years ago


What value resistor do I need for a transistor base? Answered

Hello, I am trying to work out what resistor I need to use on the base of a 2n3904 base. I am using a 555 timer to flash some leds all powered by a 12v power supply. There are 4 leds in series each with a forward voltage of 2.1v and they require 50ma. I have found that I need a 82 ohm resistor to protect the leds using a online calculator. Pin 3 is driving the transistor base and the transistor controls the leds but I do not know what resistor I need on the base. Any help is appreciated! Edit: here is the finished circuit. http://vimeo.com/33513619

Asked by Alex1M6 6 years ago


Need suggestion for clap "push Button" instead of a clap switch.?

Well I want to make a circuit that send out a "high" pulse instead of being "high" continuously and getting "low" after next clap,just like pressing a push button and not like toggling a switch a circuit that turns toggle switch signal to a single pulse

Asked by Suraj Grewal 4 years ago


How to increase NE555 output amplitude?

Hi, I have the following circuit: http://s17.postimg.org/86bus6rm7/Sawtoot_Gen.png which is able to generate a nice sawtooth waveform. When I provide 13.12 volt as power supply, the max peak of the sawtooth will be near to 8.7 volt. There is a viable way to increase this value at least to the same value of the power supply (13.12 volt)? And can someone provide me a schematic based on my circuit? I suspect that this would be viable using a transistor or an op amp on the output, am I right? If i had to implement  an op amp, I prefer to use a "single power supply" op amp, and a common IC (eg an LM358?) Kind regards.

Asked by akopelumenuscu 2 years ago



555 Timer Projects

Help me find projects using a 555 timer as many as possible. The hreater the better

Posted by e=mc^2 6 years ago


555 Am Transmitter Circuit Diagrams?

I have two ICM7555 CMOS 555 timers, and I was wondering if anyone has any good am radio transmitter circuits that incorporate two (or one!) 555 timers.?

Asked by BurningSandman 7 years ago


That I project can I make with an integrated 555?

That I project can I make with an integrated 555? i have a protoboard

Asked by mr.mister 9 years ago


Will this 555 circuit for 8 leds flashing work? Answered

Will this 555 timer work and make these 8 leds flash with this circuit I drew up.

Asked by mykiscool 5 years ago


Ps3 Rapid fire?

I was thinking of using a 555 timer to make my ps3 controller rapid fire, what do you think?

Asked by tom10122 5 years ago


How to make an LED blink using a 555 timer?

So im doing a school project and i need to figure out this whole circuit thing. my teacher recommended me this circuit (picture related) but i dont understand it. can anyone help me? i am trying to do this on a bread board (i think they're called that). i am making LEDs that are blinking using a 555 timer and a BD139 transistor. and some resistors that i dont know the resistance of.

Asked by Gaudnarok 2 years ago


Pushbutton Servo Control with a 555

I've found numerous write-ups on getting a servo working with a 555 IC but it's not quite the functionality that I'm looking for. What I'm trying to do is have two buttons go to a predetermined position but the write-ups have two buttons that just go clockwise or counterclockwise. I know this can be done with an Arduino but I'm trying to avoid that route so I can keep the footprint as small as possible. I've attached a picture of the schematic I was working from.

Posted by XAlliedYouthX 4 years ago


How do I add a delay start to my 555 chip in astable mode?

Hi all, My goal is to turn 3 bulbs on in a series. i.e. 0 min - B1 on 3 min - B1 still on, B2 on 5 min - B1 off, B2 on 7 min - B1 on, B2 off, B3 on I have decided to use 3 555 chips. May I know how can I add a delay such that their switching on and off are staggered? thanks!

Asked by pantss 6 years ago


help with a 555?

Hi, to make a long story short i don't want to have to go into the cupboard and turn on my amp every time i plug it in, it has a button on it that needs to be pressed about 5 secs after power is turned on and then left like that, could i take a feed off the power supply, connect it to the 555 or another ic and make it activate a transistor 5 secs after power was applied? i only need it to do this once every startup, i don't want it pulsing on and off and it needs to be as simple as. thanks, luke

Asked by ljarrald 7 years ago


Computer parts and others

I just basically saying 555 timers, lm386, boxs of wires, computer parts like HDs and mother boards, leds, resistors, capacitors, and other electronic componets.

Posted by Kante Tech 6 years ago


led display using 555 timer? Answered

Can anyone help me with a design , i would like to make a 5 letter display using leds that spells my daughters name "TRULY" lighting up each letters one at a time then having them all light up at once then repeat? i am new  and this will be one of my first rojects not out of a kit. any suggestions?

Asked by vince26 5 years ago


7805 and 555 timer circuit heat.

Hi all! I made a test led blink circuit with a 555 timer on a bread board. Just a basic two led blink circuit you can find all over the place. I used a 7805 for a supply regulator with power from a 9v batt. The circuit functioned fine (to my knowledge), but the 7805 got REALLY hot. I've used 7805 in opamp circuits with a 7.2v batt and no detectable heat. Is what I'm experiencing normal? Or do you believe something I did was wrong. If I remember correctly (I'm really tired as I write this) i was using 100nf caps on both ends. Thank you Nic

Posted by Mrlzeppelin 7 years ago


2 Position Servo Controller

I need some help, I am trying to create a damper control using a servo and a 555 timer. Is there anyway that you can use a 555 timer to make a servo move back and forth between 2 positions (0 degrees and 90 degrees) with an with and on/off signal and not a pot? So when the thermostat sends power, the damper moves to 90 degrees, then when the thermostat shuts off the servo returns to 0 degrees? Thanks for the help in advance. -Ryan

Posted by WingmanSVT 6 years ago


555 1 Hz pulse generator? Answered

Hi,I have a simple buzzer which I want to convert to an oscillating buzzer so as to obtain the sound similar to that of an automobile's reverse indicator.I've posted a schematic(borrowed from electroschematics.com) below.I intent to replace the LED with my buzzer and omit the resistor.I hope by building this circuit,to make my buzzer 'buzz'(or make noise) at an interval of 1 second(since its a 1 Hz pulse generator).Would the results be similar to my needs?

Asked by Adarsh_tronix 5 years ago


How to control DC motor off and on cycles. Answered

I need to control the speed at which a pager motor is on or off. I don't need to control the motor speed, just the timing of off and on. What would be the easiest way to accomplish this? (I have some 555 timers and an Arduino Uno so either of these would be preferred methods). I've tried but failed with the 555 timer and a pot to do this.  Eventually I would like to have two pager motors cycling between off and on (pulsating effect). Thank you, -shortdiesel

Asked by shortdiesel 6 years ago


Why is my 555 timer metronome circuit so variable?

I constructed this metronome circuit using a IC555 timer chip (see image below) and it worked fine on the breadboard. I wanted 2 ticks a second (2Hz) so used a trimpot to set that but was getting wild fluctuations with either the tempo increasing or really fast ticks even with the trimpot at maximum resistance. So I changed out the trimpot to a 30KR resistor and that seemed to work, but after doing the circuit nine times, it has also proved highly variable and I don't know why. I'm running the circuit on 6V (2x CR2032) and my resistors are rated at 1% tolerance. Any help please?

Asked by chiok 2 years ago


i was wondering if anyone can look at my atari punk circuit and see if maybe im missing something.

I put together a apc on my bread board using 2 555 timer ic's, looking at the schematic is seems like i did everything right, but i cant get it to produce a sound. hopefully you guys can spot what i did wrong. 

Asked by skatattookid 6 years ago


Creating a 10-15 second timer?

Hi All, Here's what I need to try and achieve: - I have a servo that I had modified and have removed the circuit board.  Now it just runs from 3 v - I want to reverse the servo once a momentary switch has been activated for 10-15 seconds - once time is up the servo reverses again I thought about using a 555 monostable circuit which would give me the amount of time, but I am unsure how to achieve everything above. I'd love not to have to use an arduino if possible. Any ideas? Thanks.

Asked by lonesoulsurfer 4 years ago


First I'm still a newbie at electronics. I know there are schematics for the "annoying cricket" out there.

Is there a schematic or explanation telling me how to make the device give a double chirp then silent for a seond before another double chirp, turning off in the light and then back on in the dark?

Asked by OnCrowsWings 8 years ago


How to make a timed LED

Hello I need help. So I want to make like a bomb timer where there is a count down and then it triggers something. It doesn't have to have a display of the numbers just like I can set it for however many seconds, then push a button.  Thanks

Posted by HavocRC 5 years ago


Heartbeat Pulse+Speaker+555 timer

Hello all! I'm posting this idea that I have for making my wife a gift for our anniversary. I'm posting this in burning questions as my research time for this is rather limited as the whole project is to be a surprise. Here's what I aim to build... What I want to make is rather simple, I want to make a pulsating heartbeat sound through either a piezo speaker or just a small 2 inch or smaller speaker. The more compact the better as I plan to integrate this into the other half of my project. The problem is im not very familiar with the 555 timer, I normally don't use them in my projects as I try to work with AC most of the time. But that's another topic. So anyways, my idea is to set the duty cycle low so it's 3 quick pulses and then about a second of silence. I imagine programming in Arduino would be easier but therein lies the problem: I do not know how to program and every Arduino I have is fried. (I make good use out of my components!) This is when I turn to the community and sincerely ask for your help in making this possible. Someone who is more familiar and can quickly and conveniently answer this is obviously more then welcome! This is where I plan on getting most of my research done in my off time. Any help is greatly appreciated. If further explanation is needed please do not hesitate to ask. :-)

Posted by 49percentGood 5 years ago


How can I make a TV remote repeatedly send a signal? Answered

Hello everyone. My parents' big CRT tv has a problem with its psu. Its probably the psu's capacitors that have died again. So in order to turn the tv on they have to click the remote's power button again and again and again for at least ten minutes until the tv turns on. It's been repaired 3 times already and because of the repair cost it's not worth repairing it again. Also because it is very big and heavy and it's very hard to move it. Their living room requires a big tv screen but at the moment they cannot afford buying a new tv. This is how I came up with this temporary solution. Make a circuit that will automate the repetitive clicking of the remote's power button, scratch the remote's pcb paint around the power button and solder this circuit. Unfortunately I'm a beginner in electronics and I don't know how to do it. I can only assume that it is possible with the use of a 555 timer and a relay. This is where I need the community's help.

Asked by myouknowwho 3 years ago


I want to design a simple circuit that drives a motor and spindle a particular distance, stops, then starts again. Answered

I want to push a button to start a platform to drive a certain distance, then hits a microswitch to stop, then I can push the same button to continue driving the same direction to the next point. The distance cannot be timed because the distance needs to be change by moving the microswitch. I would like all this to be done without a huge PCB, perferably only resistors and 555Timer. And I also want the spindle to stop even if the button is still pressed.

Asked by Uggswhiteguy 6 years ago


Schematics, Help Please

Hello, I'm trying to create a simple timer that sets off a device after a set amount of time. I'm using a schematic from a basic electronics book that my grandfather had given me a few years ago. And it seems simple enough to the point where I can understand how it works. But I just can't seem to figure out how to actually put it down on a breadboard to even test it. So if you could possibly help me find out how to place this down on a breadboard to at least test, I thank you very very much. -The picture of the schematic should be below.

Posted by caseyweed 10 years ago


How to switch between 2 outputs. Answered

Hi. I will try my best to make this intelligible. I have a chaser circuit and I am trying to get all 8 LEDs on at once when power is applied and then the chase circuit to start. At the moment I have a toggle switch which I use to switch between all LEDs on and the chaser if that makes sense. In other words, I put the switch to the left, all LEDs on. Then I switch to the right, all LEDs go off and the chaser goes on. My question is, is there a way to do this without my manual switching?  Hope this makes sense because it's doing my head in trying to explain.  Many thanks for any input this may receive.  Kind regards

Asked by LED Maestro 5 years ago


Auto restart circuit or software for external FireWire hard drives?

Hello community,  I own a few external hard drives, plugged in FireWire in the Mac, and for whatever reason, when left idle for a good length of time, they cannot spin back up, and it appears as if they crashed. Usually, I quickly power-cycle them, which seems enough to restart them but not unmount them. For the manufacturers, the drive don't have any defect as spin-down is the expected behaviour.  So currently, I was considering a crude circuit based on a 555 (I have about ten of them) or a 556 (just 1) that would automate this power-cycling, and would connect as a multiway switch. I found some long-delay repeat timer designs, but still unsure what form the final stage would be, considering up to 2A (probably more during startup) probably flow through the switch. I though about a reed relay, but they are difficult to find and quite bulky to be integrated in the external drive. The other delicate part is that the end-stage must not stay in the off state for more than about half a second, otherwise the hard drive will be unmounted The second main drive subject to this problem is more complicated, as it doesn't require any external power source but takes it from the FW port. Alternatively, I thought about a very simple (algorithmically speaking, because I know absolutely nothing there) script that would 1- detect when the drive is present. 2- When it is, every hour, delete and rewrite a small file to a partition, causing the hard drive to stay on. At least one software do that, but has an exorbitant cost of $12 to circumvent a flaw in the OS. Any idea, one way or the other?

Posted by Cubytus 4 years ago