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Troubleshooting a Positive Rising Edge Trigger Monostable Circuit with 555 IC

I've been working on designing a positive rising edge trigger monostable circuit using a 555 IC, aiming for a pulse duration of around 5 seconds. However, my simulation attempts have been unsuccessful ...
seccpur's user avatar
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1 answer
91 views

555 Monostable Mode Press and Hold Trigger

So, I have a 555 Timer in Monostable Mode, like below. I used a 47uF cap and a 47K resistor for the C and R. I press the trigger switch button and let go, and the output goes high for roughly 2.5 ...
Erik Vincent's user avatar
1 vote
1 answer
143 views

Analysis of NAND-based low-power monostable circuit

I've seen a monostable multivibrator circuit shown below. The purpose of the circuit is to provide a power to a circuit for an amount of time controlled by potentiometer after pressing the momentary ...
JSK's user avatar
  • 35
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1 answer
140 views

NE555 Delay On Off Timer Schematic

I'm trying to make a timer that turns on at a certain time and turns off after 3 seconds, i found a circuit in youtube and made it in proteus, but the output is not the same. Is there a problem with ...
Noobielectrix's user avatar
1 vote
3 answers
173 views

NE555 monoflop only trigger once on power

I'm struggling more than I probably should with this simple sounding task: The bell should be triggered once for about a half or 1 second when 12 VDC are applied. I tried to solve this with a monoflop ...
Nic's user avatar
  • 11
1 vote
2 answers
188 views

Monostable mode of ne555 is not working

I am trying to connect a 555 timer in the monostable mode. Although it is a very simple circuit, I still for some reason can't make it work. I would appreciate it very much for your help in this ...
minhaz ahmed's user avatar
0 votes
2 answers
332 views

Monostable "One shot" 555. Longer trigger than T (output pulse width) eliminator

It seemed to me that a classical "one shot" output will go low after a determined period set by T (Output Pulse Width), even if push button is held down. What I want to happen is, when the ...
Domenico's user avatar
  • 147
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0 answers
45 views

Help with using monostable one-shot multivibrator for limited time

Trying to develop a circuit that would know how to output a square wave with a duty cycle that would be controllable, and the duration would be between half a second and a second. Now I manage to make ...
Knowledge's user avatar
  • 431
0 votes
3 answers
431 views

How re-trigger NE555 timer in monostable mode while it is already triggered?

While using 555 timer in monostable mode, I want to extend the timer if trigger activates while output is active due to a previous trigger. For example if I have set the timer for 60 seconds and a ...
AKTanara's user avatar
  • 291
1 vote
1 answer
296 views

Two 555 Timers working in monostable mode, triggering each other [duplicate]

I'd like to generate a square wave signal with Ton Toff time length based on two analog voltages between 0-5V, went with the method that seems the simplest, two 555 timer ICs with their trigger and ...
fflori4n's user avatar
3 votes
3 answers
251 views

Control timing of Monostable Multivibrator

Im having a hard time really understanding a Monostable Multivibrator. What I'm trying to achieve is being able to control the timing of the vibrator with a microcontroller of some kind. (arduino, pic,...
user1728582's user avatar
1 vote
1 answer
180 views

How to change sync pulse into pulse signal

From this application note : https://www.renesas.com/br/en/document/apn/cm-318-dc-power-line-communication I want to change sync pulse into pulse to process in microcontroller I am thinking to use ...
Nott's user avatar
  • 11
0 votes
0 answers
62 views

Simple timed one shot trigger to enable LED with constant voltage not momentary switch

looking for some help on how to accomplish this. What I have is a 3 way switch (off, on (position 1), on (position 2)) powered by a 12v to 13.5v DC power source (think car battery). Position 1 only ...
PHRoGeDD's user avatar
0 votes
2 answers
39 views

How does the TI CD14538BM96 behave in response to long input pulses?

This is related to my earlier question on driving dual coil latching relays from a single logic signal. This question is on how whether the TI CD14538BM96 monostable multivibrator can be used to ...
ARF's user avatar
  • 5,219
1 vote
1 answer
169 views

How do I wake an ESP8266 when a float sensor value changes?

My goal is to reset an ESP8266 in deep sleep (pull RST low) when the value of my float sensor changes (which detects the water level in a tank), so that I can report the value change to the IoT ...
Nick Bolton's user avatar
  • 2,103
0 votes
1 answer
91 views

Monostable (eg CD4538 channel) connecting rise and fall inputs together to generate pulse from rise or fall

I would like to use one channel of a dual monostable (CD4538) to generate a pulse from either a rise or fall single trigger input feed. If I connect rise and fall trigger inputs together (or use a ...
SPotter's user avatar
1 vote
2 answers
1k views

Deep sleep wake ESP8266 with DS3231 RTC alarm

I'm trying to use a DS3231 RTC to wake my ESP8266 at a specific hour, minute and second. My circuit is a very low power design. I believe I need to reset my microcontroller (by momentarily pulling the ...
Nick Bolton's user avatar
  • 2,103
0 votes
1 answer
82 views

Optimizing RC values on monostable multivibrator accounting for retrigger timing

I am attempting to use a retriggerable monostable multivibrator datasheet to tell me if an engine is on or off. The input to the IC is a square wave usually between 100-200Hz 0-3.3V. The signal is ...
Feynman137's user avatar
  • 1,253
0 votes
1 answer
208 views

What happens if we give a negative trigger pulse before a monostable multivibrator reaches it's stable state

Monostable Multivibrator using Op Amp, from this link, Obviously there is a certain amount of time that the capacitor takes to charge again from -Vcc*β to VD (0.7v) and therefore during this period a ...
Baba Yaga's user avatar
2 votes
0 answers
138 views

Monostable multivibrator edge detector not working as expected

I have the following circuit that consists of a Monostable Multi-vibrator, SN74LVC1G123 configured to detect a falling edge upon button press and outputs a logic HIGH which in turn is inverted using ...
Adnan's user avatar
  • 111
0 votes
1 answer
651 views

Minimum time pulse for the NE555

I want to know if the pulse period of the monostable multivibrator using NE555 can go down to around 200ns. I don't have necessary equipment to test it and I'm afraid the timer can't work with that ...
Sairext Irkaris's user avatar
0 votes
0 answers
240 views

One shot monostable multivibrator with OA, output active low

I need to make a one-shot multivibrator with a OA, since in the main design, one OA is available form a package with 4 (single supply). Triggering can be either POS or NEG since I can adapt the ...
yo3hcv's user avatar
  • 573
1 vote
1 answer
351 views

Why am I getting an "invalid expression" for output voltage and not for other voltages?

I have designed this monostable (one-shot) vibrator using the 555 timer, yet I am getting this type of error on Pspice for the output voltage only. Where have I gone wrong?
Projkt88's user avatar
1 vote
1 answer
238 views

555 timer monostable → simulation is not working

I would like to build a simple circuit with a 555 timer, in monostable mode (monoflop). I looked at these two diagrams for this purpose. http://www.learningaboutelectronics.com/Articles/555-timer-...
Daniel's user avatar
  • 333
0 votes
1 answer
213 views

How to connect the output of the 555 in monostable mode to an optocoupler?

I currently have the following schematic for my circuit: Link to the simulation. On the simulation everything is working pretty good. The output of the 555 which is in monostable mode is giving ...
hello_world07's user avatar
0 votes
2 answers
223 views

555 PWM Checker/Filter

I need to design "PWM Checker" or filter - that will check that the input signal is at specific frequency (let's say 1 kHz) and specific duty cycle (let's say 33%) and the design has to use ...
Ron Vaisman's user avatar
0 votes
1 answer
607 views

OUTPUT pin is not going LOW in 555 timer IC

I was working on a simple monostable IC project and I came acroos this problem. When the switch is closed which triggers the pin 2 and sets pin 2 on low logic OUTPUT goes HIGH. As per my settings of C ...
Anirudhdhsinh Jadeja's user avatar
2 votes
3 answers
395 views

555 timer won't trigger monostable mode unless I add a switch between R12 and ground?

I have this setup which is a part of a bigger circuit to control motors. This is supposed to be a timer in monostable mode with about a minute of hi output when triggered. The lines going down are to ...
Swooperman's user avatar
1 vote
2 answers
470 views

Usage of 555/556 Timer as a One shot timer

Im using two 555 timers / one 556 timer IC for a project. I've used it a couple of times before but never in monostable mode. Basically I need to activate a DC Motor in one direction for a set amount ...
Raphael's user avatar
  • 11
0 votes
0 answers
66 views

Toggling between astable and monostable input to dual 555 timer pulse generator

Hi there, I am looking to build a simple analog circuit to generate adjustable pulses for a medical device. The current circuit utilises 2x LMC555 timers - one in an astable configuration to generate ...
Alex Mitton's user avatar
0 votes
1 answer
127 views

555 timer IC unexpected pulse wave width problem in monostable mode

I was trying to make a monostable timer for a specific project which should trigger output high for around 5 seconds. For that, I have chosen a capacitor of 4700uf and a resistor of 1K. According to ...
Subha Jeet Sikdar's user avatar
3 votes
3 answers
4k views

How to build an arbitrary (one-shot) pulse generator?

I need a circuit/IC that can generate a single pulse with a variable pulse width (I would want a minimum of 50 ns but if that is not possible the next minimum can be 1 μs, and even if that is not ...
paulplusx's user avatar
  • 314
0 votes
1 answer
83 views

My NE555 circuit triggers falsely when connected to the mains using a 5V adapter

I have designed a laser security system using an NE555 in monostable mode with a potentiometer to adjust the pulse length. Another NE555 (U2) ciruit is used for delaying power on the monostable ...
Hanzala19's user avatar
2 votes
1 answer
202 views

Tacho signal for LED fan monitoring

I am struggling with this problem: I have a fan whose output tacho signal is a square wave when it is running properly. If the fan stops the signal remains at its last value (either high or low). I ...
amsi's user avatar
  • 41
0 votes
0 answers
102 views

What is equation for the 555 timer control voltage in monostable

How do i get the 555 timer in monostable output frequency when there is voltage apply at control voltage. I only able to find the formula for astable which is Orignal post:- What is the equation for ...
i suck at programming's user avatar
1 vote
1 answer
905 views

Reset and trigger 555 timer with one push button

I want to turn on a LED with a single push button. When the button is pressed, the LED has to be turned on for an X amount of time. But what I also want, is to turn of the LED with the same push ...
leon bouman's user avatar
2 votes
0 answers
332 views

How does the loopback on a non-retriggerable monostable work?

I understand how to connect a monstable multivibrator to be in the non-retriggerable mode. Just loopback the /Q to the falling edge input or the Q to the rising edge output) as in the following ...
Francis Poirier's user avatar
-1 votes
1 answer
756 views

How to bypass continuous input on Trigger pin of 555 IC after some time working in Mono-Stable/ One shot version?

I configured the 555 IC such that it gives the output pulse for 3 Seconds (Approx.) as soon as there is input on trigger pin, but my project requirement is; even if there is input continuously on ...
Ashish Jog's user avatar
3 votes
1 answer
247 views

What is this circuit called?

This is a circuit I made to create a high signal when a switch is opened and closed. The duration of the signal can be adjusted by changing the capacitors and resistors. It is also low powered when ...
John-Arvid's user avatar
0 votes
1 answer
851 views

555 timer not working in monostable mode

I am a newbie electronics learner and trying my hands on 555 timer to get it running in the monostable mode. Am trying the circuit as in the attached diagram. I am just unable to get the LED blink. I ...
Anurag's user avatar
  • 153
0 votes
1 answer
51 views

Switching circuit based on clock

I have attached the timing diagram. I want something similar to monostable multivibrator but with so additional features. don't know how the circuit will be. Case 1: I want the output to go high at ...
Srijib Mandal's user avatar
2 votes
3 answers
497 views

Pulse output only from switch toggle on OR switch toggle off (not both)

I found this circuit here from a few years ago, posted thanks to tcrosley: Using the 74LS122 I found that it produces a short pulse both on latching the input high AND to low. The problem is I can't ...
Tim Higham's user avatar
0 votes
1 answer
61 views

How to find the exact value of K for SN54LS123

I have a circuit containing SN54LS123 (Datasheet) IC. I want to know the output pulse width but unable to figure out the value of K. The formula is PW = K * R * C. The values of K is given in the ...
user777304's user avatar
1 vote
2 answers
669 views

Replacing an NE555 with a 74HC123D

I want to replace an NE555 with a 74HC123D in a battery powered device. It is used to clock a CD4017, for which I need a pulsed signal of 46Hz. I read that a 74HC123D needs less power than a 555. How ...
user3435167's user avatar
-1 votes
2 answers
145 views

Can we trigger a mono-stable multi-vibrator( using 555 IC ) using mono audio signal?

I'm working on a project where, a certain low frequency audio spike should trigger the mono-stable multi-vibrator. If we can trigger a mono-stable multi-vibrator using a mono audio signal, how much is ...
Beginner 's user avatar
0 votes
1 answer
652 views

How to stretch 1ns pulse into a 5ns pulse?

We have a time-tagger device that records the arrival of a LVTTL signal with 0.5ns resolution. Currently the 5ns LVTTL signal is generated by a separate commercial Avalanche Photon Diode but I would ...
Toby Jackson's user avatar
0 votes
0 answers
101 views

555 Monostable delay circuit misbehaving

I have designed a basic application of a 555 in a monostable configuration to delay the LOW/off state of an output signal. (The output drives some power electronics through an optocoupler). As per my ...
Michael Fotopoulos's user avatar
3 votes
1 answer
461 views

555 timer that does not output low when reset

I'm trying to design a circuit with the following goals: When not active, output can be either Vcc or floating When triggered by pressing a button, output pulses several times to GND at some ...
Ryan's user avatar
  • 33
0 votes
3 answers
716 views

555 timer with controllable reset

I have a 555 monostable set up which is triggered when an output from another circuit goes low. This then remains on for 10 s. This all works almost perfectly. My issue is that when the output from ...
OwenG93's user avatar
0 votes
2 answers
130 views

Trouble with engineering project - 555 timers

I'm currently finishing my GCSE engineering project and I am attempting to use a dual 555 timer circuit as a timer. I am using a schematic I copied off Kitronik Alarm Project Kit, but when simulating ...
J. Doe's user avatar
  • 3