Questions tagged [555]

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation and oscillator applications. The part is still in widespread use, thanks to its ease of use, low price and good stability. The 556 timer is simply two 555 timers in a single package.

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2answers
57 views

Electronic bell for lecture [closed]

please help me about this project. I want to make electronic bell. Which duration time is like 10.45 AM to 11.45 AM ..1st lecture 11.45 AM to 12.45 PM .. 2nd lecture 12.45 PM to 1.30 PM lunch break ...
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289 views

Chicken coop door opener circuit

I'm designing a circuit that will open a chicken coop when the sun comes up. I've attached a bungee cord to the door which opens the door when a pin is released. This pin is released by a car door ...
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224 views

Wireless charging

I am trying to make a circuit to transfer power from one coil to another I have tried difference frequencies here are the results Fun Fact: When I am producing frequencies between 20Hz and ...
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2answers
159 views

Can someone explain how this circuit works? I have an idea but I dont know if its correct

What circuit does is turns the lights on sequentialy like on this gif. What I think is happening is that the capacitor thats connected between ground and the output pin through that 4k7 res is slowly ...
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3answers
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Problems with Atari Punk Console circuit

I am trying to build an APC using the following schematic: And the output is having some issues. Sound only comes out when the rightmost potentiometer is at 0 resistance, and in that position the ...
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4answers
2k views

Is there a small (6-pin) DIP I can use to generate multi-MHz squarewave clocks with an external crystal?

I'm building a circuit that I'd like to run at 8 MHz to begin with, but I want to be able to try it out at 10, 12, 16, 20, and, maybe, 25 MHz. I know that many microcontrollers have the ability to ...
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199 views

555 Timer Circuit Simulation Generates an Error

I simulated the circuit below: The expected output is a 50% duty cycle 40 kHz square wave but the simulator (MultiSim) generates an error and doesn't compile. The error message is as follows: "A ...
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1answer
67 views

Obtaining data from parallel port without the “phantom power” problem

After making failed circuits in the past, I learned that the cause is that the parallel port was producing "phantom power" (aka powering the circuit). This is because I plugged my circuit into the ...
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2answers
314 views

Very weak LED dimming with combined PWM signals using 555 timers

First of all, here's the circuit: What I'm doing here is using 2 PWM signals generated by 555 timers to control the warmth of the LEDs and the brightness. The top 555 is the brightness control and ...
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2answers
184 views

How to minimize DC brushed motor arcing noise propagation from MOSFET drain to gate?

I designed a basic on/off control circuit using 555 timer for a 3v hobby dc motor as shown in below. Without the motor connected, the output off the 555 timer is as shown below. (the mosfet drain is ...
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116 views

what type of switch would this be?

what type of switch will normally be off/ open but when activated and held in the on/ closed position will then go back to the off/ open and rest when the switch is released? I am wanting a to make a ...
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141 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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1answer
388 views

Why are MOSFETs switching at a different speed than the one they are being driven at?

I used a 555 oscillator to drive a MOSFET array for my entry-level tesla coil setup. When I measure the frequency at the driver output (Location #2) everything seems normal. When I measure it at the ...
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230 views

Problem with dual led flasher 555

I have this schematic: which supposedly makes the two LED flash alternatively with a period of 1.5s The thing is that the one connected through the NPN transistor flashes, but in it's "off" state, ...
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1answer
323 views

H-Bridge: forward and backward dc motor with ic 555 by esp8266 gpio

Searching on web for make h-bridge to forward and backward dc motor with ic 555 by microcontroller ESP8266 GPIO (PWM), i found some helps and i did this circuit: This circuit always stay with +3.95v (...
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3answers
76 views

555 timer oscillator schematic question

I found this schematic, which in theory alternates the LEDs like in railway crossing lights. First of all I was wondering if it works, and if it does, what frequency does it have, and what would I ...
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1answer
174 views

Can we use 555 timer in automotive electronic circuit? [closed]

Can we use 555 timer IC in autmotive electronics design? If not then please suggest an IC in order to create dealy at laod side.
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1answer
214 views

555 stepper motor controller

I need to make a square wave generator to control a stepper motor driver. It needs to be controlled with a potentiometer and get an output range from 40 Hz to 4 kHz. I don't know a heck of a lot ...
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1answer
987 views

555 fading in&out if possible with pwm & led array

i'm new here and also in the electronics world so pls be patient with my ignorance. I's now months that i'm fascinated by the 555 timer. The stuff you can do with such a tiny thing is impressing. ...
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1answer
332 views

Spice simulation of 555 flasher will not oscillate

I am hoping that this is a very simple question. I am trying to simulate the circuit in ngspice, but it seems that the oscillation will not initiate. I delayed the on pulse, but the expected 20Hz ...
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0answers
80 views

NE555 monostable timer circuit restart timer when trigger grounded in between [duplicate]

I had made an NE555 timer IC based delay circuit (monostable mode) which keeps output HIGH for 10 seconds when trigger pin is connected to ground momentarily. But what I want is if I ground trigger ...
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2answers
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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
235 views

Power Supply for 555 Timer LED Fade In/Out

I am a complete electronics newbro. I am looking at building a small circuit for a couple of home made modelling projects. I am following http://www.instructables.com/id/ThrobbingFading-LED-with-555-...
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1answer
154 views

Atari Punk Console with 7400 chips?

How would I create a stepped tone generator using 7400 logic? For the first part, it's easy to have same range generator, with an additional transistor. Is there any way to make the same range a ...
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2answers
311 views

Electronically adjustable PWM with 555 timer

I would like to create a PWM generator with a 555 timer (like suggested here), but I would like to be able to adjust the duty cycle with a microcontroller. I would simply use PWM from the ...
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5answers
2k views

Simple Mosfet driver

I need to switch 8 IRF9540 (P-Channel Mosfets) with about 32kHz (so 1 MOSFET about 4kHz) so that only one is On at one time. I thought about using the decade counter 4017 for this, and the 555 Timer ...
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1answer
202 views

Ringing in the output of 555 timer

I am using a 555 IC to get 10KHz-50% square wave.Everything goes as expected Except for large ringing(About 2V above the normal 9V high voltage) during the rising Edges of output. I put 0.1uF and ...
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1answer
166 views

How can a flip flop alternate between two clocks, turning one off and the other on and repeating?

I am just experimenting with flip flops and am pretty confused about alternating between two clocks. Right, so I want a pulse to be sent to a flip flop first after 18 seconds and then after 2 seconds ...
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2answers
429 views

How does the NPN transistor in a 555 timer discharge the capacitor when the output is low?

I am new to electronics and I'm trying to understand how the 555 timer works based on the diagram below. I am following the tutorial/explanation at https://www.electronics-tutorials.ws/waveforms/...
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1k 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
95 views

Resetting 555 via Transistor (optionally driven by Touchplate/Piezo)

Right now I am using a 555 circuit to generate a 1kHz square oscillation (not displayed below). Generally the reset is pulled down, but through a button I drive a transistor to output the square ...
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1answer
1k views

How to get more efficiency out of 555 timer + MOSFET?

I needed to build a delay circuit so I'm following this guide: http://www.learningaboutelectronics.com/Articles/555-timer-delay-before-turn-on-circuit.php Using this circuit, I get a delay of about 5 ...
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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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161 views

555 astable - frequency not linear with discharge resistor for smaller resistor values

I'm trying to use a 555 timer to create a variable frequency from a resistance, the output frequency should be about 1 kHz up to 300 kHz. I'm using a TS555CN CMOS version, which can oscillate up to 2....
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319 views

How to block DC of triangle waveform from 555 powered by single supply?

I'm using a 555 timer to generate a triangle waveform with a DC offset. I would like to feed the waveform into a comparator along with an AC signal with zero offset to get a PWM signal, so I need the ...
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2answers
174 views

What is incorrect with my 555 LED flasher circuit?

I have built a circuit to flash an LED using a 555 timer IC, but it doesn't flash... the LED just stays on steadily. -- I carefully followed the instructions on a common tutorial, which is: http://...
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9answers
4k views

How do I produce a 1Hz clock output using a 555 timer IC? Are there better ways other than a 555 timer IC?

I've been messing up with timer ICs, looked up on how they work and now I want to design a simple digital clock using a 1Hz pulse generator. Is a 555 timer IC sufficient enough to make accurate 1Hz ...
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2answers
5k views

Is there a way to control the PWM duty cycle of a 555 timer without using a variable resistor?

I need to control the duty cycle of a Pulse Width Modulation (PWM) circuit from a DC voltage input. To do this, I've been looking into 555-timer circuits - but every circuit I've come across involves ...
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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. ...
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2answers
558 views

555 timer circuit with d type flip-flop

Found this circuit for a 555 timer. I can't understand the use of the d-type flip-flop. Please explain.. And is the variable resistor used to adjust the frequency?
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86 views

Replace button by a component/circuit in 555 diagram

I need your help im crazy with this, i already tried many ways to do it, i need to replace the push button in this circuit by a component or circuit to be activated for a signal of 5 v such as a ...
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2answers
715 views

Replacing push button by transistor in 555 circuit

TL;DR: I need to replace the button S1 by a circuit/component that could close the circuit which the button is closing by applying a 5V signal (with 0.5s duration) in the new circuit/component. Well, ...
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1answer
202 views

What is the diode for in the astable IC 555

I am trying to get my head into electronics, so my teacher challenged me to find out what this diode does. I have done a ton of experiments and i just cant put my finger on it... Everything from ...
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1answer
243 views

12V variable-speed fan as a function of temperature using 555 timer

I would like to turn the car fan into a variable-speed fan using a the analog temperature sensor of the car, and a 555 timer. While temperature decreases, resistance (of the sensor) increases. Can I ...
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4answers
3k views

Resistance to Digital converter

I am trying to make a digital ohmmeter on a parallel port interface that can measure resistance with at least 95% accuracy. I have tried a 555 timer monostable assembly which generates a pulse with ...
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2answers
672 views

555 timing capacitor discharge via threshold input

The circuit below is the timing logic for the SC280 UV exposure unit. Based on my judgement the design of the circuit is poor - and I'm planning to replace it -, I'm posting my question only to learn ...
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7answers
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Using microcontroller as oscillator for high voltage power suppy?

MightyOhm has designed a geiger counter which is here. I am not very clear but I think he is using the 555 timer as an oscillator in the high voltage power supply section. I've attached his schematic ...
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3answers
3k views

556 dual timer circuit not clear to me

I have the following question about a cascade 555 timer circuit. The thing what I do not understand in this schematic how the second input trigger (2) is triggered for low condition. I know that the ...
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1answer
423 views

7805 Voltage Regulator powering astable 555 Timer yields LOW voltage as input to timer circuit

Hello stack exchange, So, I have two batteries powering a circuit and I want to only use one. 12.7V comes from a lead acid battery, and the smaller one is a stack of 4xAA that yield around 6.4V. The ~...
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1answer
164 views

how can i add more leds to police light circuit?

This project uses a 555 timer and a 4017 decade to produce the flash police lights. This circuit has only 4 leds , 2 blue and 2 red. I want to connect in 16 leds ( 8 blue and 8 red ) is that ...