Questions tagged [monostable]

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1answer
84 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 ...
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0answers
40 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 ...
2
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1answer
43 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 ...
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2answers
25 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 10s. This all works almost perfectly. My issue is that when the output from ...
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0answers
23 views

How is trigger initially higher than vcc/3 in 555 monostable timer?

I get that the trigger must be lower than vcc/3 in order for the comparator to show '1'. But initially how is the trigger higher than vcc/3? In some text it says trigger is initially vcc and so ...
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2answers
102 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 ...
2
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1answer
95 views

Can an electrolytic capacitor be charged reversed bias by a small voltage? [duplicate]

In this monostable circuit the C1 capacitor is reverse biased. When T1 is closed and C1 is discharged what will happen on the right side of C1? Will it charge up to 0.6 volts so that T2 can be ...
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1answer
92 views

Capacitor charging voltage showing ripples on scope. Origin?

I have an RC circuit delivering a square signal via a standard 555 timer set in monostable. I am powering the 555 with 4.88V DC directly from the Arduino, which itself is taking its power from the ...
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1answer
39 views

monostable 555 timer - buzzer motor and pulsing

I need this circuit to pulse an LED while running a buzzer motor for an adjustable period RV1 and C1 should give me 1 - 5s of pulse, while RV2 and C2 should adjust the LED ramp times The LED will be ...
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2answers
41 views

Comparison of 1G123 to 4538

I am designing the edge detection circuit with predefined output pulse duration. Pulse width will be 18.33 ms, supply power is 5V. Error tolerable is +-1 ms. There're a number of designs already ...
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1answer
55 views

IC 555 as monostable multivibrator

How is the output of a monostable multivibrator affected if the trigger pin is kept at a negative voltage (0V)? The upper voltage reference comparator will change its output to logic 1, while the ...
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1answer
41 views

Speed of monostable circuit

i need to find a time between rising edge of input signal and generating new output state. I dont have a scope so i cant measure Does someone have imagine how fast it is and how the edges looks like?
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1answer
48 views

Can I use the oscillation frequency equation for this circuit?

I'm not really sure if this is a question that can be answered so I'm sorry in advance if it isn't. I've just started doing electronics on a breadboard and I'm making a "Mini Strobe Light" from Jaycar'...
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1answer
53 views

monostable Eccles - Jordan multivibrator, theory

I’ve a few problems and questions to the principle of monostable multivibrator’s work. Basic schematic is as below: What is the reason for D1, C1, R3 elements at input? Why I can’t just tie a ...
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1answer
92 views

Why is the potentiometer setup in this configuration in this 555 circuit

I just started learning about chips and signals using the book Make: Electronics, in one of the circuits, used to generate a pulse in Monostable mode a potentiometer is used to vary the pulse length....
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2answers
460 views

One-shot Monostable 555 with long trigger

I am building a one-shot monostable oscillator using 555 Timer. Trigger pulse is controlled by a pushbutton, and thus can be long. I don't want output pulse to stay high for that long (simulated by V2 ...
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1answer
159 views

Expected behavior of 555 timer in monostable mode

While assembling the 555 timer based circuit below I noticed that 1) the intended delay on pin 3 only works if the switch on pin 2 is closed before attaching the circuit to the 9V power supply. ...
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2answers
383 views

Using Timer 555 to obtain a frequency multiplier

How can I use a timer 555 IC to obtain a frequency multiplier? I made a frequency divider by using a timer in monostable mode but a multiplier looked difficult. Can somebody tell how can I design a ...
0
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1answer
131 views

Keep Blowing out 2STN1550 Transistor [closed]

I'm (Trying) to build a trigger timer for an air cannon to launch ham radio antennas. This is an attempt to only allow the valve to stay open by a consistent interval to get max distance without ...
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2answers
123 views

How does this TLC556 work?

I'm having trouble understanding what the upper part of an electronic metronome depicted in the below schematic does. I already asked about the lower op-amp part in another topic, but I also can't ...
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2answers
404 views

Designing an Over-Current Protection Circuit with Delayed Reset

As part of a larger design I am trying to monitor current through a wire and cut it off if it exceeds a threshold. After the current has been turned off it should remain off for a minimum time period ...
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0answers
222 views

A monostable multivibrator using two NPN transistors works as desired in LTSpice, but in reality is very different

I designed a simple monostable multivibrator to extend a pulse of width \$\approx\$ \$1{\mu}s\$, to \$8ms\$ (to illuminate an LED when something happens on a bus). This is the circuit here, and the ...
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0answers
713 views

555 Monostable when switch is held for a period of time

I have a problem with the 555 delay before turned-off. The problem is that I want the time cycle to start after the switch is released if it was held for a period of time. I found this circuit at "...
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1answer
104 views

Monoshot false triggering and latchup problem

I use a monoshot to extend the duration of a short duration pulse (few microseonds) to 150 milliseconds. The issue is that the monoshot undergoes false triggering in the absence of valid input: The ...
3
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3answers
912 views

How to determine the saturation level when an opamp schmitt trigger starts worknig?

The Opamp inverting schmitt trigger is constructed as shown. The output signal is So I ask why is the output at the start of operation saturated to positive? Also, if the input voltage is moved ...
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1answer
1k views

Why does this Edge Trigger Work on input of 555 monostable config?

I recently wired up a 555 timer in a mono stable configuration and found that when the trigger was held low for longer than the configured output pulse width, the output would stay high. After ...
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0answers
213 views

Holding Reset State Low longer with hardware 555 Timer

I have a 555 one shot timer circuit in which the Trigger and Reset pins are tied together in attempt to reset the timer every time the timer is triggered so that the one shot really extends for the ...
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1answer
141 views

Interfacing retriggerable oneshot with optocoupler

I'm trying to interface 74HC123 monostable with 6N137 optocoupler. Signal from optocoupler will turn on MOSFET driver. Monostable outputs correct signal when optocoupler is not connected - 200 ns ...
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1answer
173 views

SN74LVC1G123 Monostable Multivibrator IC

Good afternoon, I was hoping someone could help me understand some of the terminology in this data sheet and how I translate that into a basic one-shot multivibrator that is retriggerable. http://...
3
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2answers
948 views

Question about comparator and 555 timer circuit

I'm designing my first circuit for a university project. This circuit will check the voltage of two sensors. If both are over a reference voltage and persist as such for more than one second, a relay ...
4
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1answer
1k views

Reset 555 timer when trigger switch is released

I have a simple 5 second Monostable 555 Timer circuit. Trigger Pin (#2) is connected to a momentary push switch. When it is pressed, the timer is started and LED stays on for 5 seconds. What I want ...
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1answer
328 views

555 timer monostable operation not so stable

I'm experimenting with a bunch of Texas Instruments NE555P IC's that I bought recently from Amazon, I made a basic monostable operation circuit on a breadboard with the following schematics simulate ...
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1answer
2k views

Monostable out of NAND gates

For the diagram below, I can see that it functions as a monostable (I have built and tested it), but I can't really see why it works, I mean, I can see that there is an RC network, which a monostable ...
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3answers
4k views

Dual edge detector

I am designing a hobby project that will run on a battery so I am trying to reduce power consumption. The SoC I am using has the ability to go into a deep sleep mode where it consumes very little ...
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1answer
209 views

How can I toggle a one shot during the timing cycle?

I need a non-retriggerable one shot circuit (monostable) that will turn off during the timing cycle if a second input/trigger pulse is received. I.e. I wish to have a single momentary switch to start ...
0
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1answer
240 views

Monostable Multivibrator

I am doing an experiment on Monostable Multivibrator using IC 555. But, I need to generate a trigger source (which goes into pin 2). I have a 5V supply and IC 555 timer. I have used R1 as 100K and ...
2
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1answer
133 views

Why does this dual monstable not function as such?

I have wired up a simple circuit here to test the cmos one-shot multivibrator. The top half of the chip seems to work but the bottom half does not. I even replaced the chip with a new one and I get ...
2
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1answer
934 views

What does the diode in this D flip-flop “One-shot” do?

Does this diode help discharge the capacitor once the flip-flop is reset? Thanks in advanced. (Image was taken from http://educypedia.karadimov.info/library/oneshots.pdf)
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2answers
305 views

How to reduce a pulse voltage maintaining a high impedance?

I have one pulse with 200ns and 60 V. I have to reduce this voltage until 10 V min because of the monostable multivibrator. After this, I will extend the pulse with a monostable multivibrator and then ...
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1answer
908 views

Monostable multivibrator with NAND gates

I would understand the behavior of the V_C potential in this circuit. The IN-M voltage is a pulse wave with 5% duty cycle. I think that it works in this way: When the IN-M is HIGH the NAND 1's ...
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1answer
110 views

monostable reverse

when the monostable is triggered the output would come on after 5 seconds and stay on for some time. switch SW2 is the reset. how would I do this? please make it simple.
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2answers
266 views

18 VAC “OFF->ON” transition detection on multiple independent power sources

I am looking for a (simple) circuit to monitor between 1 and 16 independent 18 VAC power sources, all sharing a common ground. While some might be OFF and some might be ON, the monitoring is about ...
1
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4answers
451 views

555 monostable/astable on one chip

Is there any way to use a single 555 chip which could be switched with a two-state switch between monostable mode (one-shot pulse of a certain width) and astable (continuous pulses of a certain width)?...
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3answers
422 views

Monostable circuit

Please, I need simplest possible monostable circuit (with like NE555, 74121, 74123 etc.) that will provide output like in this diagram .I am wanting to limit the time that the output is high ...
1
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1answer
285 views

Monostable Multivibrator One Shot - action with input held indefinitely

Looking for a one shot IC, that will produce and complete the predetermined output pulse (about 15ms) despite the input, that gave rise to said pulse, held constant. The reset needs to be ...
0
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1answer
40 views

Transforming impluse to DC Current

I have a source of power in form of a single impulse (around 40V for a fraction of a second), I need to convert it to a constant 12v for a longer time (like a tenth of a second) to power a small IC. I'...
5
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2answers
17k views

555 timer, one shot trigger

I'm trying to create a circuit that will pass a 12V pulse on the rising edge of a push button (it can be triggered by the entire input pulse but rising edge preffered). I've had some experience with ...
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1answer
1k views

Problem in Proteus With 555 monostable trigger

I try to make a MonoStable in proteus. Below is my circuit: But my output pulse width is dependent on the trigger circuit. For example in the above circuit according to the formula $$T=1.1RC$$ I ...
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3answers
694 views

wiring 555 to disconnect itself from electricity

i had idea for a circuit with 555 and here is the IDEA: circuit is stationary somewhere, it is in "passive state" meaning its drawing no current from battery and pin 3 is set low, then someone comes ...
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2answers
67 views

Monostable stable state

I've just been learning about the monostable circuit in electronics and have a question about its function. So, we have this circuit: simulate this circuit – Schematic created using CircuitLab ...