Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

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.

1
vote
1answer
37 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. ...
0
votes
2answers
74 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
votes
1answer
69 views

Is there such 555 timer circuit?

I was wondering if there is a simple 555 Timer circuit, or even simple transistors circuit, that has a HIGH output for 1sec, 2sec, or more seconds when I trigger the input switch and will remain HIGH ...
4
votes
1answer
87 views

How to avoid this voltage when I turn on the circuit?

What I want to do is an Delay ON, but when I press the switch this voltage pass for a brief moment and turns the led on for a moment. How can I avoid this? Should I put the switch somewhere else? ...
0
votes
0answers
70 views

How does the capacitor charge and discharge in this configuration?

I wanted to build a metal detector using 555 timer and I found this circuit online along with a video of the working model. It says that the timer works in astable mode. But since the capacitor is not ...
1
vote
0answers
31 views

Retriggering 3V PIR sensor with 555 timer circuit and LEDS

Hi y'all I'm putting together a PIR sensor circuit that will trigger a 555 timer in monostable and run a set of LEDS for about 5 sec all on a 3v cr2032 button cell battery and than reset until next ...
1
vote
2answers
47 views

Hold Pushbutton for soft latch after X seconds

What I'm trying to achieve is have a momentary push button that must be held for say 5 seconds before latching on permanently. But the button must be held for entire duration or else timer will reset....
1
vote
3answers
108 views

PWM dimmer for off-the-shelf 12v LED bulbs

I am building a PWM dimmer for loads of up to 10 off-the-shelf 12v LED bulbs. Here is my current circuit. I'll describe a fundamental problem and I ask if I'm missing something here. The driver (...
0
votes
1answer
111 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 ...
-1
votes
1answer
80 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 ...
0
votes
0answers
54 views

Safety of an Inverter Circuit

I built this circuit for an EL driver/inverter I found on this website: https://dcroy.blogspot.com/2011/02/ The transistor is a TIP122 Darlington transistor and I used this transformer in the circuit....
-3
votes
1answer
93 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
81 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
92 views

What all do I need for a simple speaker circuit?

I'm trying to use a 555 timer in astable mode to play a square wave sound out of a small speaker, but I'm having trouble understanding all the components I should use. I think I need something like ...
0
votes
3answers
87 views

Can I use a mosfet as a switch to power arduino?

I have a project in which I intend to use a NE555 timer to turn the arduino on/off on specific intervals. I don't want to use the ne555 output directly because of the current limitations of the chip. ...
-1
votes
1answer
91 views

Why Arduino does not suit the to trigger a Spark plug but 555 timer can?

To trigger a spark plug and to control it using an Arduino, I tried following this really well-written guide. Basically, a MOSFET(IRF540N in my case) controls the closing and opening of the primary ...
0
votes
1answer
70 views

Can a 555 output be made to pull to ground?

I have design in Multisim with a 555 timer that I want to pull to ground when the signal changes. It's a missing pulse detector for resetting an mcu. Is there anyway I can achieve this with say a ...
0
votes
1answer
65 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
2answers
55 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 ...
2
votes
2answers
208 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 ...
2
votes
2answers
128 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 ...
5
votes
4answers
1k 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 ...
0
votes
0answers
43 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 ...
0
votes
0answers
41 views

Can you suggest a latch circuit that ignores short duration triggers?

I am looking for a circuit which I can adapt to CNC machine to monitor a panel indicator LED to trigger a solenoid. Since CNC controls are a very mysterious and expensive I don't want to connect ...
0
votes
1answer
46 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 ...
0
votes
1answer
90 views

555 circuit problem.. could it be broken?

I've made a circuit that's connected to a 12V+5V power source (attached a gallery. last photo is the schematic) it is simply a 555 timer that goes off whenever one of the two input pins goes high (...
1
vote
2answers
71 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 ...
4
votes
2answers
118 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 ...
1
vote
2answers
73 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 ...
0
votes
2answers
61 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, ...
0
votes
0answers
86 views

PWM and PPM using 555 timer

I get what PWM is and how it can be done using a 555 astable circuit. However I feel I don't completely get what PPM is how its circuit works. I understand the VCO circuit, but I don't see how it can ...
-1
votes
1answer
88 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 (...
-1
votes
3answers
61 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 ...
1
vote
1answer
85 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.
1
vote
1answer
42 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 ...
0
votes
1answer
56 views

Low cost PWM sweep

I have this project where I need to try and get a PWM duty sweep starting at around 30% up to 100%. The issue I have is that we don't have anything left in the design (BOM Cost). I would normally use ...
0
votes
0answers
19 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 ...
-1
votes
1answer
105 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 ...
1
vote
2answers
76 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 ...
1
vote
2answers
198 views

What is the best oscillator to be used in a capacitive soil moisture sensor?

I am working on this project where I am going to make a soil moisture sensor. The principal that I'm going to use is the change of capacitance of the soil with moisture. What I'm going to do is make a ...
0
votes
1answer
112 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 ...
0
votes
0answers
16 views

Switching timer delay, non accumulative

I am a real noob at this and I haven't been able to find my answer anywhere. I am trying to build a 555-timer that delays the switch of an input signal, both ways. When input goes high there should ...
2
votes
5answers
453 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 ...
0
votes
1answer
98 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 ...
0
votes
4answers
172 views

Arduino watchdog with 555 Timer and a MOSFET

I want to protect an Arduino from stop running using a 555 timer. I saw some projects that use the Arduino RESET pin to do that but there are cases that my Arduino project still stop working even when ...
1
vote
1answer
77 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 ...
1
vote
2answers
117 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/...
0
votes
0answers
124 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 "...
0
votes
1answer
44 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 ...
1
vote
0answers
51 views

Resistor for transistor base

Inverter Circuit I intend building this circuit however I am limiting the amps (Ice) to 2.5A. Therefore I need the appropriate resistor (R3). I have the following questions: Is the output voltage ...