Questions tagged [ne555]

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1answer
38 views

AM circuit LTspice

I have to analyze the following circuit and understand its function. As far as I understand the top part is the simple phase-shift oscillator generating output sine wave at circa 145kHz. The NE555 is ...
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3answers
89 views

how to solve the phase shift of a ne555 timer

Why is the first pulse wave is not the same as the rest of the wave in this 555 timer? Is there any way to remove the wave before 2 ms or is there anyway to make it same as the rest in the graph.
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0answers
45 views

Schmitt trigger using NE555P gives wrong output

I am trying to create a Schmitt trigger using NE555P to generate square pulses from some periodically changing signals. I used the following circuit diagram and applied some sinusoidal waves (3.3v). ...
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1answer
85 views

Want to replace push-button with IR receiver

In the diagram below I want to replace that push-button switch Sw1 with IR receiver, I tried a lot with different combination with IR receiver and tried with transistor but I failed, so, please how ...
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1answer
36 views

Calculating resistor values for N3904 transistor

I'm using an N3904 as a not gate to trigger a 555. What resistors do I need? I don't know how to For R_I I want to: limit ...
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1answer
36 views

convert momentary switch to toggle switch using 555

this circuit diagram is used to convert a momentary switch to toggle function , how can i extend the diagram to get three output stats to switch between two LEDs and an off state if it possible
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2answers
61 views

Boost Converter Stuck at Around 80 Volts

I'm building a boost converter that utilizes a 555 timer switching at 60 kHz at a 96% duty cycle which drives an IRF3205 MOSFET to power a hand wound inductor (calculated to have ~330 uH) with a 6A10 ...
2
votes
1answer
116 views

Why can this ignition coil driver circuit not produce high voltage but only ~ 300 V?

Why is this ignition coil driver circuit not working correctly? (The coil is of this type, but used the model shown in the photo below.) The coil is driven with 16 V @ 5 A @ 540 Hz but I cannot get ...
2
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2answers
37 views

Resetting 555 via Transistor - RESET PIN LOW TOLERANCE

I have a circuit with a NE555DR timer that generates a pulse. The reset is held low and lifted when a voltage of 5 - 24V is applied to P0-3. A PNP transistor MMBT5401 that pulls pin 4 to ground when ...
1
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2answers
71 views

Trigger & Reset 555 same button

Been working on this for a while. Circuits are not my strong point. Power Source =5.5v dc The first image is a 4093 NAND that another used helped me with. It changes a dual led from one color to the ...
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2answers
85 views

NE555 in a light detecting circuit

I'm completely new to electronics but my degree gives me a basic course with a project at the end. I built this small circuit to detect when a light is shined on the LDR to turn on an LED so ...
17
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5answers
2k views

Is the NE555 the IC I need, and if not, what do I replace it with?

I've noticed that whilst I have a well-known solution using an NE555, that IC doesn't fulfill my needs perfectly. Others have told me that the NE555 is very rarely an appropriate solution to one of ...
1
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1answer
243 views

2-channel dimmer from NE555 + LM358?

I have a 12-24 V dimmer for LED strips like this: https://www.circuitlab.com/editor/#?id=c8m48y simulate this circuit – Schematic created using CircuitLab I want to understand a couple of ...
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2answers
133 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 ...
5
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3answers
2k views

555 timer frequency is way off

I'm currently designing a 555 timer to provide a 38kHz square wave to drive an IR LED as part of a beam interrupt detection system. This beam interrupt is a part of an embedded product where we ...
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4answers
160 views

Turning on LEDs [closed]

I started a small project where I want to have three LEDs which are turning on gradually (in first step just one is on, one second step two are shining and then all three). I've tried doing it via ...
5
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3answers
119 views

Why won't this 555 timer flashing circuit work?

The circuit which I made shows the following behavior, when power is given to the circuit: Sometimes it lights up, sometimes it doesn't. When it does light up, it flashes properly for a few seconds ...
1
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1answer
142 views

Need help in designing of circuitry. (Power Electronics)

The circuit is supposed to detect ambient light and react accordingly. When there is high illuminance the LED should be dim and when there is low illuminance the LED should be bright. The transistor ...
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0answers
115 views

Over current Protection for Ne555 circuit?

I made simple frequency generator circuit with Ne555 but almost in every circuit Ne555 IC burns after few use. Ne555 starting to heat up then outputs weird signals , if I don't stop the supply Ne555 ...
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3answers
67 views

How to connect LED to output device to show the output state without any voltage drop so that it can be sensed by MCU?

I am using an NE555 timer to get output from one of my output device. The basic function of NE555 timer here is to toggle the output of my output device which was successful but I need to attach a LED ...
0
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0answers
47 views

Convert NE555 square wave output to triangular wave using op-amp(s) [duplicate]

I want to generate a square wave with 45% duty cycle and 465Hz on an NE555 timer and then convert that wave into a triangular wave using op amps. I have a circuit schematic but the output generates ...
0
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1answer
56 views

Connecting Ne555 chip's 7 discharge pin directly to supply

I'm building a adjustable frequently generator with ne555 timer . But I don't want duty cycle to change with frequency so Can I connect the 7 discharge pin directly to supply and add a potentiometer ...
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1answer
79 views

Two questions about astable multivibrators and transformers

Here's something that confuses me: The output on an astable multivibrator will be shown on a multimeter as half the input voltage (for example we have 9V-0V-9V-0V...and the multimeter averages it out ...
0
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1answer
398 views

How to operate a 12V/5V NE555 timer relay from 12V DC supply and Capacitor

Problem: I need to switch ON a NE555 timer relay from 12V DC supply When the DC supply is switched ON. Also, when I switch OFF the 12v DC supply, the relay should switch ON again as it is a timer ...
2
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1answer
84 views

Multiple NE555 timers, disable retriggering until all have finished

I plan to build a small timer device that, when triggered, lights up 3 leds. After 30 min, the first goes dark, after another 30 min the second and yet another 30 min later the third. It's pretty ...
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1answer
74 views

Review inverter design: why are there no short circuits?

I made my first inverter design and I got a lot of help from this website. But I want to get your suggestions before something goes wrong. Circuit output is 12V AC 72Hz square wave. I used NE555 as ...
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2answers
103 views

NE555 LDR threshold voltage

The problem is that when I set the LDR on my car and stop for a short time near street lighting my headlights from the car are switched off. I made a circuit simulation, when I click 4 times for the ...
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2answers
109 views

Can I use a 555 PWM signal to control

I want to use a 555 PWM signal to control a motor. I also want represented the speed of the motor with an LED graph using a LM3914 led driver. Can I use a digital signal to control the LM3914 ...
3
votes
1answer
666 views

555 timer delay circuit + light sensor?

I am quite new to electronics and I would like to combine these 2 circuits together so that during complete darkness on the LDR, the LED would turn on instantly and when light falls on the LDR there ...
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3answers
157 views

Why output is high even though trigger pin is high in Proteus simulation of IC555?

In the below attached circuit of IC NE555 Proteus 8.0 simulation, TRIGGER pin (Pin 2)is set at Vcc. So why the output is high? It should be low since voltage at TRIGGER pin (Pin 2) is more than 1/3 of ...
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1answer
444 views

NE555 and LDR circuit diagram

I have modified a schematic for my project with the following image: Instead of a 20K potentiometer, I use 100K for more precise adjustment. Do I need to add a disk capacitor of 10nf or 100nf to Pin ...
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1answer
202 views

Why is this circuit not working?

I was making this automatic street light project with a slight change i.e replacing LDR with vibration sensor on proteus. While using LDR it worked well as it changed color depending upon light (red ...
3
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1answer
133 views

How to get a better square wave out of ne555

I built a basic astable circuit for the 555 and I'm using an oscilloscope to view the output. I know this IC is supposed to output a square wave but instead I get these slopes (I don't know what to ...
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3answers
749 views

555 Clock Circuit - how to choose resistor value? [closed]

I need to design a 555 clock circuit to output a clock pulse of a specific frequency. The circuit I'm using is this one (from here): I've used this circuit before and it works fine but the website ...
5
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2answers
194 views

555 Astable Timer produces incorrect period/frequency

I am building a 555 astable timer circuit for a course which must match the BPM of a song. The song has a BPM of 104, which requires a timer frequency of roughly 1.733 Hz. The circuit looks as ...
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1answer
87 views

Doubt about a NE555 [closed]

I created this circuit a few days ago, but I'm a beginner in electronics, so I do not know if it's well done This circuit causes the LED to turn on after 5 seconds and to keep it on Could someone ...
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1answer
319 views

Astable 555 not oscillating [closed]

I've been struggling with building a 555 timer for a project. I get the expected voltage at pin 3 (output), but the problem is that it's not oscillating. The Vout is constantly 8.4V, while I expected ...
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2answers
861 views

Changing frequency of 555 timer with varicap or capacitor

I have created a 555 oscillator circuit where the output is set to have flashing LED light. Now I have a problem when I change the voltage of the potentiometer, the output frequency does not change. ...
0
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1answer
154 views

NE555 Circuit stops working after random time

i finished my NE555 circuit and created some pcbs. After a few attempts i could get the circuit working, and tested it successfully. I placed my circuit between a 12V 1.5Hz square wave signal and a ...
0
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1answer
93 views

Strange behaviour of ne555 + pmosfet circuit

I was a silent reader for a long time and could solve all the problems on my own, but this problem is really freaking me out. I was messing around until 3 AM today with this "feature" and still don't ...
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5answers
1k views

What to make with hundreds of 555 chips [closed]

This is a little bit different question than normal.. Aliexpress is ruing my life, sometimes i order things i don't even need because it seems cool. A few time ago I ordered 500x 555 chips for just a ...
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0answers
49 views

Determine the frequency and on time of two coupled ne555

I've the following circuit: I use it as a voltage controlled pwm generator. My question is, how can I find the frequency and on time of the PWM. I tried changing all the resistor and capacitor values ...
0
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1answer
122 views

Is there anything wrong with this particular timer circuit utilizing 555?

I created following simple timer circuit for one shot operation. My expectation is it to give 5v as output (for D RELAY and SP RELAY) for certain number of seconds/minutes soon as it got powered-on. ...
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2answers
239 views

NE555 Controlled Transformer Voltage Spikes

I am attempting to build a NE555 timer controlled step up transformer (3:250). R2 and R3 will be variable resistors when it is completed. Input is 12V and I'm stepping that up to about 1000V. The ...
0
votes
1answer
334 views

Vibration sensor switch for Car

I am building a small GPS tracker for my car using a Raspberry PI Zero plus some additional components. I would like to keep it off unless the car is turned on or it's moved forcefully. To do that I ...
0
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3answers
612 views

Installed 555 timer socket backwards - can I reverse the chip in the socket?

I installed the socket for a NE555 timer ic backwards on a PCB. Can I just reverse the chip in the socket to cure the mistake?
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2answers
710 views

Repair help. Mosfet keep shorting

I have "repaired" a cnc power nad speed control board from yoocnc (china) and it worked fine for a day. the next day the spindle just started running as power was applied. the mosfet was shorted, the ...
1
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1answer
763 views

Very Basic 555 Timer oscillator not working

I've been trying to make an LED blink. My first approaches were without the 555 timer, and they were unsuccessful. I decided to make an Astable multivibrator circuit. I'm using an NE555, and I'm using ...
0
votes
1answer
226 views

555 - HIGH then long delay [duplicate]

I trying to create a circuit with only one 555 to send HIGH on output(3) for very short time, like 200ms, then set LOW for something like 20~30 seconds. Then I'm just need turn on circuit, then: a) ...
2
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3answers
4k views

Can I place a relay at the output pin of a 555-timer

I recently remember running across a bunch of articles on web about the 555-timer, it’s my first IC. I’m getting more familiar with it, and I want to know run it in a-stable mode, with a relay ...