30 Threads found on edaboard.com: 555 Timer Delay Off
I need to build a simple delay off timer. When the input is triggered (pulse only) the output must go high and stay high for a period of say 1 hour or 4 hours or selectable. When the input is triggered again, the output timing is restarted.
Any idea's? Would a 555 timer work? Not sure about the long (...)
Professional Hardware and Electronics Design :: 20.11.2006 04:11 :: mikesmixes :: Replies: 1 :: Views: 2285
I wouldnt use any of those for your application.
You want a loud buzzer, well you can get a cheap piezo that'll produce 100db's, which is annoyingly loud, getting that from your own circuit requires complexity.
I'd use the above piezo on a monostable to give the time delay.
A standard monostable 555 circuit would work fine, you'd need a 22
Hobby Circuits and Small Projects Problems :: 23.08.2010 23:39 :: dr pepper :: Replies: 1 :: Views: 1637
Sorry for being so unclear.
The fan is mains (220V) operated, and the toggle switch is part of the mains power, switching the lights on-off.
The delay off electronics is 12 V operated, and gets its power from the permanent phase and zero lines.
The coupling between the low V and the high V circuits is made with relays.
Hobby Circuits and Small Projects Problems :: 05.08.2013 01:09 :: Yossef Gofer :: Replies: 2 :: Views: 460
i have uploaded a corected version to
so check it out.
The idea is that you calculate the time on for the 555 timer i added to the time it takes to scan through the LED sequence and the time off to be the delay u want.
Hobby Circuits and Small Projects Problems :: 29.06.2007 18:37 :: ultrabrains :: Replies: 6 :: Views: 1333
Read up on the 555 timer chip. This will give you the delay you need for a small LED to remain alight for say 30 seconds after you close the door. You will have to take a trigger from the courtisey light to activate the 555 timer
Hobby Circuits and Small Projects Problems :: 18.12.2007 06:27 :: barrybear :: Replies: 1 :: Views: 1433
555s can be very fickle when used in timer mode, they are very prone to false triggering when near any source of interference. I think you will end up tearing your hair out when used in the presence of an electrically noisy motor. You can buy timed off relays with variable timers. Also as Banjo suggested, a cheap micro (...)
Hobby Circuits and Small Projects Problems :: 14.10.2008 08:33 :: GrandAlf :: Replies: 6 :: Views: 4600
I think you can use a 555 with a relay.
Electronic Elementary Questions :: 18.02.2009 12:16 :: VVV :: Replies: 7 :: Views: 1376
You really need to post your schematic. No one is going to know the exact Maplin circuit you "robbed".
Take a look at:
This is the basic 555 monostable circuit. One problem is charge stuck in C1. If you close the switch for several seconds, open the switch and then close it again quick
Hobby Circuits and Small Projects Problems :: 18.05.2009 22:42 :: banjo :: Replies: 4 :: Views: 9722
When the compressor stops you have the falling edge of 12V signal that operates the compressor ..
You can use it (through a capacitive coupling) to trig the 555 timer (simple negative edge one-shot) to generate a 2-minute delay ..
Then, you can connect the output of the 555 and the voltage that operates the compressor (...)
Electronic Elementary Questions :: 27.06.2009 23:54 :: IanP :: Replies: 1 :: Views: 1791
Hi guys i need a timer relay for my car.
I already browse the forum but still confused.
I need a 555 based power-on and power-off time delay relay(separated circuit).
The time must be adjustable and i need a regulated power supply for the circuit.
I also need to know how to calculate the timing of 555. (...)
Analog Circuit Design :: 30.07.2009 00:57 :: lanz :: Replies: 1 :: Views: 1563
Check for "555-circuits" or 555 timer/555 monostabil multivibrators & even general: triggered timer circuits...., we have such at EdaBoard too...
Simplest solution is for you: per switch loaded serial RC element of 1uF & ca2.7MOhm to basis of a transistor, their Collector/Emitter has your relay...
Electronic Elementary Questions :: 17.01.2010 06:53 :: karesz :: Replies: 3 :: Views: 2686
Power-on delay can be realized in several ways, for example with the very popular 555-timer, but I would like to encourage you to use a small microcontroller, some times called the 555 of the new millennium, namely the PICAXE08 ..
You shouldn’t have problems in buying it in Australia (Altronics) ..
Analog Circuit Design :: 16.02.2010 09:07 :: IanP :: Replies: 3 :: Views: 703
I want to add a timer circuit to a led flashlight so after I press the 'on' switch it will shut off after a few minutes automatically
1. It has to be small
2. it works on 3 AAA cells possibly nimh so v~1.2*3=3.6V
3. no drainage during the many many hours when the light is off (either main switch off or (...)
Analog Circuit Design :: 10.03.2011 07:54 :: shalomw :: Replies: 4 :: Views: 1058
You could use a 555 timer i.c. in the monostable mode.
The output would switch a relay with more than one set of contacts. One set, in parallel with the button contacts, would close and maintain the power until the end of the 3 second pulse - at which time the whole thing is automatically switched off.
The other set of of contacts (...)
Analog Circuit Design :: 14.05.2011 09:23 :: Syncopator :: Replies: 7 :: Views: 6870
I'd like to design a circuit such that at first, the circuit is completely powered off. The user pushes a switch, which injects power into the circuit. Then a mechanism maintains the power active, even if the switch has been released. At a later about 3 seconds, when the circuit does no longer need power,
it cuts its own power and sleeps u
Analog Circuit Design :: 20.05.2011 02:00 :: purpleanger :: Replies: 6 :: Views: 947
You can use TSOP1738 IR receivers. They are easily available and are commonly used in TV remote control receivers. But they are excited only by an IR radiation of frequency 38kHz. So, you also need a 38Khz astable oscillator using 555 timer.Refer the following circuit for emitter. For that entry and exit thing try using a flip-flop as Magnatro
Hobby Circuits and Small Projects Problems :: 28.10.2011 04:33 :: freddyp007 :: Replies: 5 :: Views: 2481
Do you mean you need a delayed starter?
You could use a 555 timer and connect it's output to a transistor to power your LC circuit.
Analog Circuit Design :: 08.11.2005 23:45 :: Lord Loh. :: Replies: 5 :: Views: 729
how can i get a 8 Hrs dealy ckt for my motor contorl.
it means for 8 Hrs it should be on . after 8 hrs it should turn off automatically.
is it possible with 555 timer or any other suggession
Electronic Elementary Questions :: 18.12.2007 00:01 :: vinoddesai :: Replies: 6 :: Views: 655
please suggest a suitable IC
I think a "555" timer IC (available from a lot of semi companies) + 2 resistors + 2 capacitors will achieve the cheapest solution for your circuit 1 (NMOS driver). For more info, start here or
Analog Circuit Design :: 16.01.2010 12:18 :: erikl :: Replies: 1 :: Views: 971
I need to make a simple device which will change the current`s direction after a certain interval (i.e 5 seconds.).
Can you give me some idea or scheme of it`s construction? (Something with 555 timer would be OK.)
Thank you in advance...
Hobby Circuits and Small Projects Problems :: 28.02.2011 05:40 :: imperatormk :: Replies: 19 :: Views: 1472
You can use a 555 timer
555 and 556 timer Circuits
Electronic Elementary Questions :: 28.06.2011 16:40 :: alexan_e :: Replies: 5 :: Views: 552
I'am new to this forum and know a little about electronics. I''m also thirteen.
I searched the forum for a similar project.Before posting here.But? Could not find any thing to what i need.
I build a astable 555 timer for clocking the time period of 10s appox
five secs (On) five secs (off). Just to learn how the (...)
Professional Hardware and Electronics Design :: 13.10.2011 21:02 :: Ebonic :: Replies: 62 :: Views: 3661
Hi guys. I'm new here so a little back'ground. I'm an automotive mechanic with a background in automotive electronics. that being said I'm working on a project and while I do work on automotive components this goes a little deeper than I ever need to go. I need a component that I can momentarily trigger to energize a relay for 5 seconds. I hav
Electronic Elementary Questions :: 30.10.2012 00:06 :: newb12 :: Replies: 7 :: Views: 412
if you want to do it by cheap cost just use a relay only and avoid using triac
by using microcontroller you can create 5sec delay ad trigerr your relay only for 5sec and after that make your microcontroller pin as low
or you can create it using 555 timer if you dont want to use microcontroller but the problem is after very 5 sec pulse will (...)
Power Electronics :: 06.01.2013 12:10 :: nikhilt007 :: Replies: 3 :: Views: 275
For a first guess, have a look at 555 timer application notes. If you want zero current consumption in off-state, a different approach might be required, e.g. using CMOS logic ICs or transistors.
Hobby Circuits and Small Projects Problems :: 26.07.2013 05:42 :: FvM :: Replies: 34 :: Views: 952
You can use some kind of timer or counter supplied and started from the first regulator (4060 or 555). The output of the timers start the second regulator.
If the regulators you use do not have an On/off control you can use a P mosfet to connect the output to the load.
Electronic Elementary Questions :: 16.12.2006 08:18 :: cesare :: Replies: 5 :: Views: 1777
Type general family of circuit you need is called a missing pulse detector. Below is a link to an example. This can be done with existing timer or oscillator chips, like the 555. Or, as you mentioned, it can be done using a small microcontroller. Using an exisiting multivibrator chip or timer is usually faster to design. However, the (...)
Hobby Circuits and Small Projects Problems :: 14.08.2009 07:54 :: banjo :: Replies: 9 :: Views: 5828
This is a clever circuit and practical as well.
However it puts low-power circuitry in close contact with high power...
In such a case you need to ensure cooperation between the two.
This circuit should be tested in sections. The timer circuit should be tested for proper operation without being hooked up to the welding circuit.
Then take the n
Analog Circuit Design :: 05.05.2011 23:14 :: BradtheRad :: Replies: 4 :: Views: 1388
Hi all I'm a complete noob at writing code for micro-controllers basically want i want to do is...
I'm upgrading my previous Lead-acid battery desulfator from a 555timer based osc with LVD to a pic12f675 (or 629) running a 3mhz osc (555 was a nosiey bugger lots of harmonics audible).
So I've got super simple code set to pulse Mosfet at (...)
Microcontrollers :: 09.03.2012 22:38 :: ghead :: Replies: 1 :: Views: 495
555 is very handful for your problem.
Hobby Circuits and Small Projects Problems :: 01.03.2013 13:01 :: ahmad1954 :: Replies: 1 :: Views: 436