Questions tagged [ne555]

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5
votes
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 ...
1
vote
4answers
157 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
votes
3answers
113 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
vote
1answer
134 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 ...
0
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0answers
59 views

Back EMF protection

I made an ignition coil driver circuit which is nothing special - they are everywhere on the internet. What's really bothering me is the back EMF that would fry the 555IC. If I put a rectifying ...
0
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0answers
90 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 ...
1
vote
3answers
62 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
41 views

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

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
votes
1answer
52 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 ...
0
votes
1answer
57 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
votes
1answer
178 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 ...
1
vote
1answer
78 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 ...
0
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1answer
71 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 ...
-2
votes
2answers
79 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 ...
0
votes
2answers
74 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 ...
0
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0answers
74 views

Combined a 555 dimming circuit with a 555 blinking circuit into a 556, LED flickers during dimming

As the title says, I have put together 2 555 circuits (dimming and blinking) into an NE556. I added a switch to toggle between blinking and dimming and used it to drive an LED. However, I noticed ...
3
votes
1answer
438 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 ...
0
votes
3answers
79 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 ...
1
vote
1answer
257 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 ...
0
votes
1answer
178 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
votes
1answer
112 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 ...
1
vote
3answers
605 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
votes
2answers
166 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 ...
-1
votes
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 ...
-3
votes
1answer
234 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 ...
0
votes
2answers
595 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
votes
1answer
127 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
votes
1answer
83 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 ...
9
votes
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 ...
0
votes
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
votes
1answer
115 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. ...
1
vote
2answers
211 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
303 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
votes
3answers
503 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?
0
votes
2answers
621 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
vote
1answer
627 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
178 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
votes
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 ...
10
votes
2answers
3k views

NE555 Based Speed Controller circuit - Contradicting Pins in 2 Tutorials

I am a newbie of Electronics and learning it as a hobby. Over a course of time I realized that Electronic Blogs are not the best place to learn Electronics, unless you have a strong basics and can ...
3
votes
1answer
487 views

How do I reset NE555 output to LOW when powered on?

Here is a functional NE555 push-on push-off switch. But the problem with this is whenever the power source is connected, it starts in random On or Off position. How to modify it so that it always ...
1
vote
2answers
536 views

Cannot Understand the 555 IC Reset

I have designed the schematic diagram of the inner components of the 555 Timer IC for understanding the working of the IC, but not sure if I have designed it correctly or not. If it is correct can ...
2
votes
2answers
3k views

independent control of frequency and duty cycle in 555 timer (formulas)

I want to control frequency and duty cycle of output pulse of 555 timer. I searched and find this schematic in a post in SOV but I don't know how calculate frequency and duty cycle in the circuit. ...
0
votes
3answers
2k views

Using a NE555 for 12V boost to 24V to power an amplifier

I'm trying to draw a supply scheme for a class D integrated amplifier. It requires 21V to 24V power supply and about 6/7A of current at 24V. The input is a car battery: 10V to 14.4V. I found this ...
3
votes
2answers
2k views

NE555 above 100kHz frequency problem

At first I searched this problem and could not find anything with this specific. I am using NE555 to generate frequencies. I'm using the calculations of this website. I am using 10nf as it says. My ...
-3
votes
1answer
375 views

Constant power supply with countdown timer triggered by a momentary switch

Can I make a 1 or 2 NE555 timer delay switch adjustable module from eBay,or any other simple components ? Momentary switch closes = power ON and start of a countdown timer of 0.3s. Mentary switch ...
0
votes
1answer
70 views

Two Astable NE555 Affects one another

I have two separate breadboards, on each breadboard I placed NE555 and both are configured in astable mode. Breadboard 1 is configured to 200Hz @ 50% duty cycle and Breadboard 2 is configured to 1....
0
votes
1answer
303 views

Photoresistor with NE555

I would like to build a circuit with two blinking LEDs using a NE555 timer and a photoresistor. In the schematic below the blinking frequency becomes higher when more light shines on the photoresistor ...
0
votes
1answer
172 views

NE555P Frequency Drop to 0 after a couple of minutes? [closed]

I'm trying to build a frequency measurement circuit using NE555P and Atmega328P. The circuit is the following : I use this library https://www.pjrc.com/teensy/td_libs_FreqCount.html Always, The ...
2
votes
1answer
980 views

Offline Flyback DC-DC converter using NE555, Works in LTSpice, will it work in a real world application?

I'm currently a novice and am learning EE. I've been experimenting with low voltage DC-DC converters. Now I want to build an offline DC-DC converter that operates directly from AC mains. The ...
-2
votes
3answers
280 views

What would be the lowest cost approach to a low power, up to months-long timer?

I'm looking for a starting point. I wish to make a very small circuit (SMD, something like 2cm x 2cm PCB) low cost (translating to hopefully well < $1 at production). The circuit would provide a ...