1000 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 :: 11-20-2006 04:11 :: mikesmixes :: Replies: 1 :: Views: 2339
Need a 1 minute on and 3 minute off timer using LM555 and a relay.
Hobby Circuits and Small Projects Problems :: 01-27-2006 13:34 :: fjpompeo :: Replies: 1 :: Views: 2121
for this you have to connect it with the ldr tha a delay circuit and then a 555 timer it will gives you more accurate idea how the circuit hsould work
Electronic Elementary Questions :: 02-03-2006 07:45 :: vicky :: Replies: 5 :: Views: 2524
This website should help you:
Hobby Circuits and Small Projects Problems :: 12-28-2008 00:59 :: DrWhoF :: Replies: 1 :: Views: 2323
to reduce the current consumption , when LEDs are off is
to include a transistor in series with + line and controlling its base voltage with the sample from pin3 of 555.
in which case the switch SW1 may be moved across the series transistor .
Hobby Circuits and Small Projects Problems :: 08-10-2010 10:04 :: srizbf :: Replies: 3 :: Views: 2808
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 :: 08-23-2010 23:39 :: dr pepper :: Replies: 1 :: Views: 1668
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 :: 08-05-2013 01:09 :: Yossef Gofer :: Replies: 2 :: Views: 495
For 1), you can use two 555. The first one as a monostable and the second one as an astable. The astable period be the blinking period of the LED diode. The monostable period should be 5 second. The monostable output (3) should be connected to the reset pin (4) of the astable.
Electronic Elementary Questions :: 10-18-2004 07:17 :: papyaki :: Replies: 7 :: Views: 1727
Im using the AM Transmitter and Receiver Pair along with the RF600 enoder and decoder.
I have constructed my PCB, the output is going to a 555 timer with a basic pair of LEDs and a buzzer.
At the moment when I press the learn switch the status LED on the decoded goes on but when I let go, it goes off again.
I have this working on (...)
RF, Microwave, Antennas and Optics :: 10-02-2005 14:06 :: mhamini :: Replies: 0 :: Views: 483
all u need it a 555ic u can easily get delay of ur choice it have very simple ckts,by that u can switch on/off any thing by attaching it to relay of ur specified voltage.also u can use 2 ics in order to do ur job in a bit modified manner
Mathematics and Physics :: 10-16-2005 17:45 :: malikanwer :: Replies: 1 :: Views: 750
This circuit appears to be a zero-crossing detector. The edges of the square wave correspond to the zero crossing of the incoming AC power line frequency.
While you could easily produce a 555 timer circuit that had an output at twice this frequency, it would no longer be correlated or synced to the power line frequency.
What exactly are you
Hobby Circuits and Small Projects Problems :: 03-27-2007 13:40 :: banjo :: Replies: 4 :: Views: 1982
Have a look at:
There is a Relay Toggle Circuit Using a 555 timer.
Electronic Elementary Questions :: 08-26-2007 06:21 :: dunn :: Replies: 15 :: Views: 4591
ok so my teacher wont accept the fact that the circuit he has told everone to use isnt even going to work... he has refuses to let us make our own but i dont realy care as it isnt reght that we all have to use the same circuit cos its easier fr him...
so if anyone has any clues of what way i would go about doing this please tell me
Hobby Circuits and Small Projects Problems :: 09-28-2007 06:25 :: devildonebad :: Replies: 3 :: Views: 1391
Yes, it is possible, but you need more than one 555.
Can you describe the application a little better?
Analog Circuit Design :: 10-09-2008 12:27 :: VVV :: Replies: 4 :: Views: 897
And what this 555-timer suppose to do there :?:
Microcontrollers :: 04-13-2010 10:17 :: IanP :: Replies: 11 :: Views: 1381
I've seen realistic results out of LTCSpice using the model
off their Yahoo! user group repository.
You should be aware that the 555 does not produce truly
square (50/50) output for most sensible RA/RB ratios.
Read the app notes if this matters to you.
Analog IC Design and Layout :: 10-18-2010 09:06 :: dick_freebird :: Replies: 2 :: Views: 2178
You can use a 555 timer in a monostable mode to get the desired effect. Check out this page, under monostable, and using the circuit modification mentioned in "Power-on reset or trigger" (cap in parallel with power switch)
555 timer circuits
The basics of why this works is detail
Electronic Elementary Questions :: 03-07-2011 21:41 :: enjunear :: Replies: 16 :: Views: 7641
If you are going to incorporate a microcontroller (MCU) into your design, there is no need for a 555 timer. Most MCUs have one or more timer/counters which can be used to produce a delay.
Do you have a particular MCU you were considering for your design?
Microcontrollers :: 09-11-2011 05:38 :: bigdogguru :: Replies: 6 :: Views: 1048
Google "555 astable multivibrator" and look at a few of the websites you get back. There are MANY that talk about how the circuit works... all the way down to the nitty-gritty details about the level comparisons and current mirrors inside the 555 IC.
Analog Circuit Design :: 09-26-2011 23:41 :: enjunear :: Replies: 4 :: Views: 1166
is there any chance to control the freq of 555 timer by using a microcontroller... i.e. if 555 timer is designed to certain works according to it. but i want to change the freq of 555 timer by using a 8051 mc( ON and off the 555 ic) and not by changing (...)
Electronic Elementary Questions :: 01-16-2012 11:46 :: dinesh401 :: Replies: 6 :: Views: 1067
Maybe you need to have a timer and delay using a LM555+CD4017 70183 johnson counter for your 6sec delay ?
Analog Circuit Design :: 03-04-2012 06:58 :: vimalkhanna :: Replies: 3 :: Views: 1405
Hi, I have a 555 timer 'one-shot' circuit running off 12V, which lights up 2x 1W UV LEDs (350mA, 3.4V, in parallel). My understanding is that the 555 only puts out 200mA, so I would need transistors to get full potential from the LEDs.
I'm looking at transistor calculators and reading up on it but the math/theory is beyond (...)
Electronic Elementary Questions :: 07-30-2012 00:05 :: eester B :: Replies: 6 :: Views: 464
I'm building a circuit and this is the basics of it:
After a brief delay after power-up, a latch goes from low to high and stays high until power-down.
On a more technical level:
A 555 timer starts at power up. I feed its output into the NOT-R of a NOT-SR latch[/UR
Hobby Circuits and Small Projects Problems :: 12-18-2012 02:04 :: browner87 :: Replies: 8 :: Views: 999
use 555 as a astable multivibrator use a buzzer of 12vdc
- - - Updated - - -
use this ckt
Analog Circuit Design :: 09-29-2013 05:28 :: pradeep.g.belchada :: Replies: 10 :: Views: 544
try astable mode calculator:
Hobby Circuits and Small Projects Problems :: 08-01-2014 15:29 :: js :: Replies: 4 :: Views: 340
On 2001-09-17 08:54, Robin Hood wrote:
This free 555 timer design program provides for four operation modes (3 astable, 1 monostable), plus 16 application examples, and timer/component specifications.
File size: 253KB
Thanks for sharing
Professional Hardware and Electronics Design :: 02-26-2002 23:13 :: just_one69 :: Replies: 10 :: Views: 4092
:P a nice freeware to design using 555 timer IC.
Software Links :: 02-26-2004 05:10 :: rauol :: Replies: 0 :: Views: 1110
You can for example look here:
for a 555 controlled sawtooth generator.
Hobby Circuits and Small Projects Problems :: 03-02-2004 10:34 :: C-Man :: Replies: 5 :: Views: 8460
555 timer designing soft for any circuit:
Software Links :: 05-24-2004 00:49 :: alphi :: Replies: 0 :: Views: 1751
a 150W switchmode power supply with 555 timer:
it cheapest method to design such switch mode power supply.
Analog Circuit Design :: 05-24-2004 01:32 :: alphi :: Replies: 14 :: Views: 18308
What you do is have it in the astable mode with a speaker in series with a capacitor. These tow are placed one end to ground and one end to the 555 output (this is for a CMOS type. IF the output is an open collector, use a pull up resistor.) Then have the remote button be between the power supply and the +V power supply pin of the 555.
Analog IC Design and Layout :: 04-10-2005 20:08 :: flatulent :: Replies: 1 :: Views: 2118
Check the sight www.digchip.com,register your self (it s free) on the search engine of that sight write ne555, or lm555 then download the data sheet you want as pdf file.
Added after 1 minutes:
I m sorry the sight is
Electronic Elementary Questions :: 04-25-2005 11:56 :: mohammad mokhtar :: Replies: 5 :: Views: 938
i need help with a 555 timer circuit that i am trying to design , the 555 timer is used as a LED flasher , it has three user controlled settings Low ,Medium and High.
Low denotes a time interval of 60 Min,Medium of 24 Min,High of 10 Min , the problem is i want the circuit also to compensate for the time when (...)
Analog Circuit Design :: 05-05-2005 13:40 :: risingcurrent :: Replies: 10 :: Views: 1826
It's called timer because of its use in timer applications such as square wave generation ...etc.
And the name "555" is because of the three 5kOhms resistance in its input (check its internal block diagram)
Hope that helped,
Electronic Elementary Questions :: 04-27-2006 18:57 :: ahmad_abdulghany :: Replies: 4 :: Views: 700
You can simulate the 555 in circuit maker 2000 infact there is an example circuit which demonstrates the simulation of the 555 IC in the astable mode.
I am attaching the 555 example file and a screenshot of the simulation.
Software Requests :: 05-09-2006 08:04 :: ibrahim03 :: Replies: 7 :: Views: 1681
i need a circuit for Phase shift keying.... a circuit using 555 timer would be much helpful...
Electronic Elementary Questions :: 08-06-2006 06:56 :: A.Anand Srinivasan :: Replies: 3 :: Views: 1621
Just a question regarding triggering of a monostable 555 timer, what will happen if I pull down the trigger of the monostable circuit to the ground on the ouput?
Say, I trigger it (put trigger pin to ground) and will just put it on ground (not release it), what will happen to the output? Will the monostable do its normal operation or it will jus
Electronic Elementary Questions :: 10-09-2006 01:10 :: glenjoy :: Replies: 8 :: Views: 6356
Need help please...........
is it feaseable 2 use a 555 timer in place of LM3909 to produce oscillations and how do I go about it?
Hobby Circuits and Small Projects Problems :: 10-14-2006 09:10 :: polag :: Replies: 5 :: Views: 4815
Yes, The name of 555 came from the three 5kOhms resistors at its input!
important or not, it's not clear :) as they're a part in the IC structure! and according to them it works !
I hope that helps :)
Electronic Elementary Questions :: 12-20-2006 06:57 :: ahmad_abdulghany :: Replies: 5 :: Views: 7311
That is wery simply to make seconds indication. You connect 2 7447 and 2 LED display to U11 and U12 like displays of minutes. timer 555 is not stable. You must use piezo cristall for frequency generator.
Electronic Elementary Questions :: 12-31-2006 17:06 :: Jan Iwaniuk :: Replies: 4 :: Views: 2482
I have an analog circuit with a 555 timer outputting 0 to 5V, but what I want to do is switch the high's and lows. In other words when the 555 outputs 0V, I want it to output 5V and when it outputs 5V I want 0V. Inverters only seem to flip the signal around the 0V axis (multiplying the signal by -1)
A "picture" may describe (...)
Analog IC Design and Layout :: 02-08-2007 18:51 :: trackst4r :: Replies: 2 :: Views: 730
An idea is to make two oscillators with two separated 555 chips, then using external MUX, select outputs according to its selection lines (1's and 0's)..
Or, you can use only one 555 chip, if you could put an intermediate adjustable component.. e.g. a resistance that's been shorten or something like that, when an NPN switch is ON, apply your mod
Hobby Circuits and Small Projects Problems :: 02-24-2007 23:54 :: ahmad_abdulghany :: Replies: 6 :: Views: 2814
You may like to take a look at this circuit,
generating PWM signal using 555 timer.
Electronic Elementary Questions :: 03-15-2007 09:43 :: siongboon :: Replies: 4 :: Views: 6865
Connect 4 x LM555 timers in the following sequence: RED(long), Yellow(shorter), Green(long) and Yellow again and close the loop by feeding the input of the first 555 from the output of the fourth 555 ..
Here are examples:
Electronic Elementary Questions :: 09-17-2007 11:01 :: IanP :: Replies: 2 :: Views: 2888
this is ic 555 timer calc prog with run vb4 dll
you must setup vb4 frist to run this prog
Software Links :: 04-14-2006 05:13 :: su3mb :: Replies: 3 :: Views: 4392
if you are using potentiomenter, then you require just one potentiometer and a diode with 555 astable multivibrator circuit
Hobby Circuits and Small Projects Problems :: 12-02-2007 06:39 :: yogi :: Replies: 5 :: Views: 4233
hey i don think we can implement 555timer in verilog or vhdl...you can possibly realise its functionality... like if you want a astable multivirator or bistable one... you can realise it i suppose...
PLD, SPLD, GAL, CPLD, FPGA Design :: 12-04-2007 00:44 :: lordsathish :: Replies: 3 :: Views: 2955
555 is an analog chip based on op amps and use the values f external components to select it's mode and timing .
I think this can't be done in vhdl!!!!
PLD, SPLD, GAL, CPLD, FPGA Design :: 12-09-2007 20:07 :: alzomor :: Replies: 2 :: Views: 1514
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 :: 12-18-2007 06:27 :: barrybear :: Replies: 1 :: Views: 1456
Hi guys ,
I am trying to simulate the standard astable oscillator using 555 timer, in circuit maker. But i am not getting any oscillations at all. Could you guys please help me out.
The circuit is the same that you find in most of the 555 timer books .(operation in astable mode)
Software Problems, Hints and Reviews :: 04-16-2008 15:51 :: VASANSNS :: Replies: 0 :: Views: 1383