What is Timer: Definition and 126 Discussions

A timer is a specialized type of clock used for measuring specific time intervals.
Timers can be categorized into two main types.
A timer which counts upwards from zero for measuring elapsed time is often called a stopwatch, while a device which counts down from a specified time interval is more usually called a timer. A simple example of this type is an hourglass. Working method timers have two main groups: hardware and software timers.
Most timers give an indication that the time interval that had been set has expired.
Time switches, timing mechanisms which activate a switch, are sometimes also called "timers."

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  1. C

    Should a central heating boiler be kept on all the time or on a timer?

    Yet no-one has been able to provide any formulae etc to expand the topic further. A lot is said about house construction (high mass vs low mass) but that doesn't take the discussion any further. I think the key question is if your house is badly insulated then it's losing heat all the time...
  2. harrison1216

    Powering My AC Mains Project with a Push-Button Timer

    Hello! I am trying to create a special kind of switch for a project I am working on and I am pretty stumped. Basically, I need to power a 110v fan and light for around 10 seconds with the push of a button, and then have them all turn off and be ready for another button push. My brain immediately...
  3. engnrshyckh

    Object detector using ultrasonic sensor with 555 timer

    See the attached figure. I used 220uF with buzzer and also tried 10uF capacitor but buzzer isn't loud enough. I don't have any 3.3pf capacitor. I used 1.1 pF instead. I also tried changing the resistance of potentiometer but still buzzer isn't sound loud enough.
  4. fahadnajed

    How do you make a digital counter circuit which counts to 10 minutes?

    I need to make a digital counter circuit which it counts to 15 minutes for my big project in my campus . When the circuit counts to 10 minutes, it will rings a buzzer. Same when it continues to 15 minutes, it will ring a buzzer again. (the circuit is for public speaking, so the speaker knows...
  5. AbdullahS

    Any ideas for how to read this mechanical timer?

    Hi all, just came across this timer while on a site-visit. Any idea how to read this thing? PS: if it is not a right section, please move it to the right one as I was not sure where to post this. Regards, Abdullah
  6. H

    Timer based switch for a power capacitor

    To cover transformer loss at no load and maintain pf, we are needing 6kvar at day time and 9 kvar at evening. Is there any time based switch available, such that it can switch ON 3 kvar at evening, say 8:00pm and turn off automatically at 8:00AM morning
  7. Borek

    555 timer, 50% duty cycle astable, run from 5V

    Standard disclaimer: I know next to nothing about electronics (which doesn't stop me from having fun :wink: ) I have a buzzer here that I am trying to run from an 555 based oscillator. I need around 2700 Hz and 50% duty cycle, and it would be best to run whole thing from 5V. 50% duty cycle is...
  8. Pilotman Ray

    Aircraft Start Sequence Trainer/Mockup

    I am stuck in the middle of building a circuit for an aircraft starting mockup that will train our students to correctly start the aircraft without accidentally re-engaging the starter and thus causing very costly maintenance actions. The system is 12v. We would like to have a 10 second delay...
  9. M

    Where Can I Find a 6 Hour Mechanical Timer for a Pill Bottle?

    Hey mechanical engineers, I am a biomedical engineer, I have designed a pharmaceutical dispensing apparatus that is currently powered on mechanical timers I have found online. Does anyone know where I could find a 6 hour mechanical timer I could fit in a standard pill bottle?
  10. Triple_E

    Build a Lightning Cloud with a 555 Timer | LED Flashing Help

    Hello, I have been in the process of building a small lightning cloud out of Poly-Fil and some LED's. I have looked up on how to build flashing LED's with a 555 timer, and I have tried (many) times, yet every time I hook up the 9v battery, my LED either turns on, but does not flash, or doesn't...
  11. T

    555 timer IC - Calculating resistance needed

    Voltage = 9.0 V, Current = 20 mA, Capacitor (C) = 10 microF, Resistance before (too high) [R_A = R_B] = 10 k Ohms. In a a-stable oscillator, calculating the resistance needed for two resistors (R_A = R_B) to discharge and charge a capacitor (C) so that a LED does not blow. Currently my circuit...
  12. P

    What Are Some Options for Programmable Home Automation?

    I want to switch either a standard AC socket or a USB outlet on and off on a programmed cycle. But although there are many consumer-ready timers available to do this at set times of day, programmable to the minute, I want to be able to randomize the cycles and have it programmable to the second...
  13. P

    The History of Ticker Timers in Physics Experiments

    Hi, I'm new to the forum... I just modified some ticker timers to serve as standing wave generators for my class. It got me wondering when ticker timers were first used to do physics motion experiments. I'm assuming it was from the time they had telegraphy, so maybe as early as the later 19th...
  14. P

    Designing an Electronic Timer Circuit Using NE555 IC or BC548 Transistor

    Dear I would like to design a simple electronic timer circuit by other NE555 IC or BC548 Transistor. I’ve got a circuit but it doesn’t work. Would you please me in this regard? Appreciate, if you would get back to me with tested circuit diagram at your best possible time. Regards Pervez
  15. J

    Comp Sci How to Implement a Timer in C++ for Repeating Code Blocks

    Basically within my whole code is 4 major chunks of code that each loop repeatedly. The obvious problem is when I run it, it will get stuck on the first chunk and loop forever, therefore never moving on the next chunk. What I need is to have each section run for 10 seconds and then move on. Is...
  16. T

    How to test f=ma using trolley and ticker timer?

    To test mass affects acceleration. is it correct to change the mass of plasticine attached to the trolley and measure the length of the ticker tape strip with the constant variable be the angle of the inclined plane?
  17. K

    Waterproof Watch with repeatable countdown timer?

    Part of my job as a lifeguard is dispatching guests at water slides at a busy amusement park. Believe it or not, these people paid quite a bit to get in, and I actually care about them, so I would like to fire them off at the maximum rate possible. Sadly, I am responsible for timing this - I...
  18. A

    What could be causing my destinationVariable to not update in my timer program?

    I've debugged and run my program without seeing any results from my "destinationVariable". What could be wrong? sub main() call myfunction() end sub sub myfunction() static myClock As Single myClock = timer if (timer - myClock) > 100 Then destinationVariable += 1 // This...
  19. F

    555 timer question & Bounceless Garage door opener.

    555 timer question & "Bounceless" Garage door opener. When opening a garage door from a distance, it is sometimes necessary to push the button multiple times when beyond the range of the transmitter. One can inadvertnently push the button multiple times and cancel the door going up. To open...
  20. W

    Mount a circuit with timer and led

    Hi there, I'm a material's design student and I have an idea to a project.. This idea needs an electrical circuit , with a led and a timer, but it has to be really really small, because it is for small objects. How can I mount this type of circuit, with a timer that will fire a red light...
  21. STEMucator

    Differential geometry, what book is good for a first timer?

    I've been wanting to see what this topic is all about for awhile now. I see the word "Manifold" and other terminology floating around on the forum. It got me really curious. I wonder what the prerequisites are to reading a book like this? Hypothetically I have the prerequisites, what would...
  22. C

    Engineering Burglar Alarm Circuit - Help needed with 555 Flip Flop timer.

    Homework Statement I have to construct a circuit for my Physics class. The circuit must be tripped by a CDS Cell (Detects changes in light) and, once being 'tripped' it must play a continuous sound and make an LED flash on and off. This picture is of the circuit board we are allowed to...
  23. T

    Transistor connection in the discharge path of the 555 timer

    http://www.slideshare.net/viv3ksharma/automatic-school-bell In this circuit I Think the emitter and collector terminal of the transistors T1 & T2 will be reverse. Otherwise the 555 timer will not discharge. Can anyone help pls?
  24. A

    120-240VAC Digital Logic Power Relay Timer

    Design Goal: Remove power from 4 washing machines and 4 dryers using relays and a digital logic timer. (9 Hour cycle of no-power from 22:00 to 07:00 the next day) Design Problem: What relays can I use that can be actuated by logic voltages? Should I use 2 relays, a logic relay that actuates a...
  25. A

    Creating a Digital Logic Timer for a 120-240VAC Relay System: Tips and Solutions

    Hi Guys, I'm tired of waiting for my tenants to finish their midnight laundry loads. I have a hydraulic sliding door assembly ready but I am having trouble getting parts to create the digital system to tie it all together. I want: 120-240VAC Power Relays (for the washing/dryer machines...
  26. A

    Raster Scan Generator (555 timer chip)

    Hi all, I need to create a circuit for displaying something onto an analog oscilloscope screen. I have determined it will be best to use a raster scan generator (essentially a linear ramp generator). I am wondering what might be the best way to design such a circuit in order to allow for...
  27. E

    What are my option to power a pneumatic solenoid? on a timer

    Hi guys. This is for an engr project that I am involved in. I have everything else worked out but this got me stomped. I've been searching for a while and can't find something that fits my application. basically the solenoid is controlling a dual acting air pneumatic cylinder. the solenoid...
  28. C

    What is the most energy-efficient component for measuring long durations?

    Which electronic component (or other means) would you use to measure duration, like a timer, if energy must be saves to the maximum? This component should use as little power as possible, while being able to measure duration up till 5 years with a resolution of, say 100 hours. In the old...
  29. STEMucator

    What book to use for a first timer trying to learn real analysis?

    Hey, I recently just finished my calc 2 course ( All my exams actually :) ), and I'm thinking about learning real analysis over the summer. Just to stay keen and it's a topic I'm really interested in. I've heard Rudin is a staple ( heard it was tough as well ), but I would like to hear other...
  30. W

    Need reliable electrical or mechanical 24hr timer

    It needs to perform at least 50 cycles with a cumulative error of no more than [+\-] 30 minutes. This is for a home project. Any suggestions of components?
  31. C

    Flasher, Logic and Timer circuit

    Long story short I am building a bottle rocket at uni. As part of launching this rocket we are using a flasher, logic and timer circuit. Can you please explain the basic role that each of these circuits, and an overview of the circuit as a whole. Help is much appreciated.
  32. Solarmew

    What happens when the switch is closed in a 555 timer and left there?

    Here's my circuit The question at hand is what happens when the trigger switch is closed during the timing cycle (after being closed once already to initiate said cycle) here's the waveform I'm getting, but I'm not sure what to make of it. could someone please help me understand...
  33. T

    Making a Blinking LED 555 Timer

    Hi guys, I figured I might try making a LED to phase on and off for around 1 second, to be perfectly honest I have NO idea what I'm doing really. But figured that's the best way to learn right :P. So I'm using a Timer 556 and connected it in a way that kind of made sense from the 555 IC timer...
  34. F

    Can a Microcontroller Replace a 555 Timer for a Low Frequency Flasher?

    I want to build a low frequency, uneven cycle flasher somewhere around 10 seconds on, 5 seconds off. I planned on using a 555 timer and a MOSFET to drive my load, a small DC motor. Are there any other suggestions for something at low frequency? I'm just concerned at the R and C values needed...
  35. davenn

    NE555 Timer inventor passes away

    Hello Members and Visitors Only a couple of weeks late ... it just came to my notice and scrolling back through threads I don't see any other mention Hans R. Camenzind (1934 – August 8th, 2012) was a Swiss electronics engineer best known for inventing the 555 timer IC in 1970 Sad day...
  36. B

    So what is the time taken? Help me!Thanks

    If i was running a vehicle down a slope with ticker tape attached to it, running through a ticker timer, and finding the distance of intervals of 5 (0-5, 6-10, 11-15, 16-20) and the time for each interval is 0.1, 0.2, 0.4 and 0.4.. If I already have the starting and final speed, how would I go...
  37. T

    Tesla coil with 555 timer troubleshooting help

    I attempted to build a tesla coil with a 555 timer but seemed to have failed some where. Perhaps you could take a look and give me some hints on what to try in order to make it work. I attached some pictures as well. I made the secondary coil on a 1/2 (.875 OD) pvc pipe with a 10 to 1 ratio...
  38. C

    Troubleshooting a 555 Timer Circuit with Added LEDs | Circuit Issues & Solutions

    Hello, I have designed a circuit based on one that I found on the internet (attached as example.gif). This circuit worked well when I built it on a breadboard. I made a few minor modifications to the example circuit (attached as schem1.bmp) and I am having a few issues that I do not...
  39. X

    Creating a Simple Timer Circuit without an IC

    So I started really getting into circuits about a year ago and it has quickly become my new favorite hobby. (A little background into my education, I am a senior physics undergraduate.) Since I started doing circuits I have wanted to learn everything that I can about them. I don't like using...
  40. A

    Harnessing Gravitational Energy to Create a Timer Device

    My semester project is to create a device that will make a sound at 5,10 15, and 20 seconds exactly using only gravitational energy. -My initial design used two rotating axles with two gears through them and a chain. It would begin by me dropping a weight attached to one of the axles making it...
  41. D

    Linear metal expansion - For an Old timer

    Hi all I am a newbie here, so please go gentle It is along time since I have had to use Thermal Co-efficients of expansion for various metals. However, I am trying to tie in some figures I have been given to what I know to be reality. i am sure that I am doing something basically wrong...
  42. K

    Make a Mechanical Timer: Spring vs Counterweight

    Hi, I am thinking of making a mechanical timer to control a pedestal fan. I want do a completely mechanical one, just for the feel of it. For the energy storage method, I have two options, either a spiral spring or a counterweight. Which one should I use? Any good reading material on this...
  43. K

    Construction of a Timer Switch

    Hi, I'd like to do a small design project. When I sleep, I switch on my mosquito repellant for about 8 hours. Sometimes I forget switching it off too. Such long durations are little poisonous and generally not required. What I plan to do is to make a timer with a dial from 0 min to 60 min...
  44. B

    Design 12V or 24V Timer for Hydroponics System

    Hi This is my first time on this site and it looks great so far. It doesn't matter if it is 12v or 24v either will do which ever is the easiest. What I would like is to be able to run say up to 6 12volt 5 amp water pumps for my hydroponics individually say every 2 hours for 10...
  45. R

    LM555 Timer with Motor: Easy Guide for Beginners

    Please forgive my inexperience. I am trying to put a motor , either 3v or 12v, powered by a 6v battery, on a LM555 8 pin timer. I have 30000 ohm resistor, 1000 ohm resistor, 3000 ohm resistor. I also have a 500 cuf capacitor. I would like it to go on for approx .5s and then off for 10s, times...
  46. S

    Way to check whether ne555 timer is working?

    is there any way to check whether ne555 timer is working?i got a project in my coll about seismic sensor and this is the circuit diagram http://1.bp.blogspot.com/_a-VJV2rj-08/TE3BFy92lAI/AAAAAAAAAFs/8Ugz6gINKJw/s1600/Untitled.png. when i soldered everythin perfectly,and a supply is give to...
  47. P

    Electrical DIY laser trip wire / counter / timer

    Hi people, please excuse me if this is the wrong forum to ask, I am new. I want to build a cheap DIY trip wire that records how many times it is set off. If I could use some sort of laser to be more discrete that would be a bonus (and just cooler). Also if it is possible to record the time that...
  48. K

    Request help with 555 timer circuit

    Hi all, I would like to make a 555 timer circuit that when 12v is applied to the circuit an LED will light for 3 - 5 seconds and then go out. and remain out until the 12v is removed and reapplied. Any help greatly appreciated. Thanks
  49. S

    Clap Switch using 555 timer in monostable mode(Values of components))

    Hello Experts! Here is my simple clap switch schematic. First let me know is it correct or not? I have used 555 timer in monostable mode here this means LED will remain on for the particular period of time defined by R3 and C1 i.e. T=1.1(R1)(C1). Let I use red LED here. So I think 1.7V is...
  50. S

    Monostable and Astable multivibrator using 555 timer.

    Hello experts! I have given 2 question in exams. 1)Explain why duty cycle of Astable circuit's output is always greater than 50%? 2)In monostable multivibrator, how low does the triggering voltage have to go in order to initiate the output pulse and why duty cycle must be greater than...