Search Engine www.edaboard.com

Timer 555

Add Question

513 Threads found on edaboard.com: Timer 555
First of all, hi everyone! I'm new in this community and this is going to be my first design as an Electrical Engineer. I'm getting perfect 12VAC signal with 1khz from this circuit. But when I try regulating this 12VAC to 6VDC 1Amps, I'm having huge voltage drops and regulator doesnt work. I think transistors current limits are not enough. Would
Huh? A 555 is a timer, an LM358 is an opamp. Just use a 0.1uF or 0.01uF. It will be fine.
Hi guys, I want to drive 3 leds with 555 timer, frequency 4Hz. I drive it with 9V. The leds are 1.8V@2mA I afraid it will not work properly. I will more than happy from u guys to look at it and give your remarks.. Schematic is attached. 555 timer: 135931
I am generating 300us Monostable Pulse through 555 IC with 12V Vcc supply.The frequency is 5Hz. The pulse width is ok but when I see the waveform on the oscilloscope, the pulse shape is not good. The pulse rises to 10V very fast but after that exponentially goes to 11V and while discharging it drops down to 3 V fast but then exponentially discharge
I'm trying my first 555 timer project. I was able to get a single LED to flash, however when I try to setup the two LED to go back and forth, the one "LO" Led always stays dimly lit. The instructions say this means the timer chip is bad, however I've tried about 10 different chips and they all do the same thing. Another issue I noted is (...)
I have two PWM sources to control mosfet gate driver. the first source is MCU which isn't connected all the time (when needed)(it is not on the pcb), the second is timer 555 which is connected just when i push the buttons (right or left)(manual control and it is on the pcb). I isolated the two sources with pnp transistors to connect the (...)
Hi, So I am trying to build this circuit and i basically have unlimited resources. I am running into a lot of problems with this however. It seems like every time I take a step in the right direction I take two steps back. I have a working transformer a four stage multiplier and a 555 timer. this circuit is exactly like the one presented in the fir
Hello there, Can any one please share a schematic for a delayed OFF timer circuit. My requirement is to have the Light(230V) stay ON (approx 15 sec.) from the moment it turned off from the wall switch. I currently have a CFL (23W) bulb, if its not appropriate I can replace it with a LED light. Thanking you,
It sounds as though you want multi-stage timing cycles. Here is a vast collection of circuits for 555 timer IC:
Could you be more specific? Do you want a digital circuit? An analog circuit? Any constraints? Frequency? A simple 555 timer would do this. So could an FPGA.
Hello, I'm pretty new in electronic field, but I have a question. So I have this circuit that should activate two relays, with one clap. I made a circuit build around a 555 timer, in monostable mode, and when I clap in front of the microphone it gives me at the output a signal that have a duration of 6 sec, exactly what I need. With that signal
A single 4017 IC (decade counter) can turn on your heaters, one at a time, in sequence. The IC has ten output pins, although you would only need 6 pins, each controlling a relay. Apply a pulse to the input pin every 2 hours. Each relay will turn on for 2 hours, then turn off as the next one turns
A laser emits light, so it cannot alarm (think of a torch). The reflected light from a laser can be detected and the breaking or reduction of the received signal can be used to fire up an alarm. The main problem is at the receiving end. The photo detection device will always saturate, which means that if the suns rays get into it, it will always
why not sense hotspot temp and regulate fan speed automatically. A 3 minute timer is possible with Johnson COunter and Emitter Follower or FET buffer with OP Amp Feedback to reference voltage created by 1 minute clock and 3 stage control but only using extremely low leakage plastic Caps and big >20MOhm resistors. using CMOS Schmitt trigger rela
You need to add a comparator IC that has a high input impedance to sense the capacitor voltage without loading it down. The output of the comparator can have 4mA as base current to turn on the transistor that drives a relay that needs up to 40mA. Or use a 555 timer IC to replace your entire circuit.
I was given an old Onan MCCK marine generator. The K7 relay-emergency device is crushed so beyond repair, and these parts are long ago out of production. What I would like to do is design something that would function in a similar way. The way the device works is if low oil pressure (LOP) switch S4 conducts from loss of oil pressure, power flo
In the datasheet of 555 timer, the reset pin can take voltage upto 1v(max.) to reset. Then why the reset pin is connected to Vcc(12V) for Astable multivibrator mode????
hi, To keep the cost down I would use a 555 timer as a PWM generator for each chain. For only 20mA per LED chain, from a 24Vdc source, a BJT or a 2N7000 MOSFET would be suitable. The frame frequency of the 555 PWM generator could be selected for each LED colour chain. Lots of simple circuits on the web.
help me with resistor and capacitors value:-x using 555timer circuit please
For my space requirements, a 555 timer is way to big a block to solve this problem. I was thinking of just putting something like a series capacitor which would allow the short pulses to pass through (cause its almost an high frequency ac signal) and block the wide width pulse (cause it's like a DC signal) Is this method correct/feasible?[/Q
I have a simple repeater controller using a simple timer ic which is the LM 555..du7dlz
Design square wave oscillator using 555 timer operating at 8khz with 50% duty cycle. need sample design and computation/formula. :)
I don't know, if that's the same as many of the 555 timer devices, the 555 responds to a falling input signal 2/3rds below the rail voltage, and the trigger signal has to be shorter than the output signal. I think the 558 is different, it's described as edge-triggered (don't bother even looking at it, it's available but obsolete anyway). (...)
Hi there! Sorry, I don't understand - What do you mean you are stuck with the timer? - A circuit without a 555 in it is probably lacking something, there's always an excuse to use one! But seriously, this schematic by this guy might help, I've used (or slightly adapted where necessary) quite a few of his 555 circuits and they have all (...)
I want to build a circuit that scans my 4x4 keypad using a binary counter and a '138 to generate the row scan and then read the results with a '374 which is read by the processor. The counter is clocked with a 555 timer. The counter will have to reset after it reaches 3. The resistors are pull-down. What would I use as a counter? A '161? And how wo
Hey guys In order to get a PWM signal I have chosen to use the second circuit with the Schmitt Trigger and Comparators. However the 555 timer circuit is also a valid method to obtain a PWM Signal. My question is are there any drawbacks of the 555 timer circuit so that I may explain why I chose to go with my circuit (...)
Do we need to assume ourselves that you have used 555 timer ic in astable mode and you have used BCD counter and the 7 segment display to display the timervalue?
"Voltage Controlled Pulse Width Oscillator" Found in this lengthy collection of circuits for the 555 timer IC. (Scroll halfway down.)
Hi, I'm trying to use the output of a 555 timer in mono-stable (one-shot) mode to control the rotation of a servo motor for a period of about 2 seconds. I'm using the RC period of the one-shot circuit to power a servo tester which will generate the pulses required for the servo. Unfortunately the circuit seems to work fine when connecting a LED
Hey im making a timer using ne555 ic and when i made the circuit on bread board it worked fine and tried to transfer it to vero board and it dindnt work is there any reson why it didnt work i checked the traks for solder but there wasn't any . Attached are photos of the veroboard :113518113517[ATTACH=
I guess this will help you
You could use two time-delay relays. No soldering, but lots of money. Now might be a good time to learn to solder! I would look at using a 555 timer and a couple of transistors. They are cheap and plentiful. But if you REALLY don't want to solder, you could use a breadboard.
I suspect the problem is the switch contacts 'bouncing'. I think what you are seeing is the time interval starting as soon as the switch is opened not when it is closed. If the switch is held closed, the timer will not run (as you observed) but when a normal switch is pushed the contacts open and close a few times as they collide and bounce off ea
You can make use of comparator IC like LM339 for doing so. You can use 555 timer for 5 mins. If you need more help let us know
In schematics for the 555 timer Chip in Schmatics they do not show the hookups as 1, 2, 3, 4, and 5, 6, 7, 8 in vertical sequence. Many scchematics illustrate the sequence of leads on the chip as all mixed up. The draw is clear, but the sequence as to the chip is all mixed up. How does that help?
An ordinary 555 timer uses a fair amount of battery current when it is timing. A Cmos 555 (LMC555, TLC555 or ICM7555) uses almost no battery current when it is timing. One timer IC can be the timer and a second timer IC can time the beep for (...)
The datasheet for a 555 says, " The trigger input voltage must return to be high at least 10us before the end of the timing interval". Then you must capacitive-couple the trigger pulse to pin 2 so that the trigger pulse duration is shorter than the timer output pulse duration. This Applications Note shows how to do it:
it could look like this It's not a tesla coil. Atesla coil has no magnetic coil. You have step um transformer there. Still if the IC circuit is tuned to operate at the transformers resonance frequency (probably is so), this is working on high efficiency
Hello everyone. I am designing a simple metal detector using the 555 timer. This is the the sensitivity is very poor. How can i increase the sensitivity of the detector.
A 555 timer IC is an easy and common way to do what you are describing. Below is a method which is more or less When the input goes high, the capacitor begins to charge. After a second it reaches about 1.
if you know a little electronic, you can build timer with 555 easily. just search 555 timer
It is 40 KHz Ultrosonic sensor, You can desing a transmitter with IC 555 timer, Receiver with LM386, and search google number ideas available Refer data sheet given below link..
Nikica if you want a precise timer, a 555 relies on stable supply voltage, a trimpot and very expensive large capacitors with very low leakage., making this design impractical due to the fact that most big caps have a self leakage in this range of time and going to an ultracap with long leakage time constants gets more expensive. The traditional s
This is another circuit i found recently. I built it and it seems this is working fine. When leads are shorted the meter reads fsd and to infinity when leads are open. When connected to caps the meter read between 8-10 scale on 10v range. Is this normal? Can this circuit be taken as the suitable one for testing in-circuit caps?
The attached ESR meter with 555 was built by me. This is working fine but only the meter shows FSD when leads are open. If the leads are shorted or a capacitor is connected between the leads then the meter scale moves down to 2v on a 10v scale. Is this behaviour correct. Do we have to read in reverse order since most of the meters move to lower
Can anyone explain how this circuit works ? It's working in my simulation software... I just want to know how it works. 107255
Hello, Some of the basic electronic circuits, mainly consisting of 555 timer & CD4017 and also other ICs have a range of input voltages such as the circuit could function from 6V to 9V for example. How could this be justified and explained?
I am puzzled by your question! Multisim is a schematic simulator and NOT a programming language. But you can introduce delays using RLC components or timer chips like 555 or 4538 cmos. These are not options but you have to actually connect up the components to implement your delay. Allen
Hello, I've built this simple circuit ( ) using a 555 IC to flash a LED at a certain frequency, determined by two resistors, R1 and R2. I used an online calculator ( ) to calculate which resistors/capacitor I'd need to have the LED light up ev
I am building a battery powered device (preferably 6v from 4xAA?s) that will drive about 5-10 bright LED?s for 10-15 seconds when a door is opened. When LED?s power off I would like power to be automatically disconnected altogether so there is zero residual current. There should be a trigger that restarts the timer (can be the same trigg