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 low price and ubiquity. The 556 timer is simply two 555 timers in a single package.
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How can prevent the source voltage from dropping when using a 555 timer
I am trying to use a 555 timer in my circuit to produce a signal (rather generally) above 100kHz. I have been successful with this goal, but have had an issue where the voltage measured on my positive ...
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NE555 duty-cycle at 50 Hz frequency [closed]
I'm modifying a generator to test servo motors. Originally it was controlled by a wheel potentiometer on the right or left. It generates a duty cycle at 50 Hz for a time of 1 msec rotates to the right,...
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555 circuit with high input and pulse adjustable output
I found a 555 timer that works with a pulsed input and gives an adjustable single pulse output. (see below).
I need the same circuit to work with a constant high input.
8ms input high
4ms output high
...
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Designing a power supply circuit for a DC motor speed control circuit
I am designing a a power supply circuit for a DC motor speed control circuit.
I am using Proteus to simulate it but it is not working.
I am using a step down transformer to take 230V to 16V then ...
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Time delay circuit to reverse the rotation of DC motor when input is high
I am trying to design a circuit to use to control a DC motor according to the output of a capacitive proximity detector.
The circuit should turn ON the DC motor in forward direction when the hand ...
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Sign Modulator - Class Project [closed]
I need to simulate a specific circuit, and I'm running out of time, so please someone can tell me what I am doing wrong?
I think I have this part correct:
Here starts the problems, I don't know how ...
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NE555 + CD4017 Airplane Strobe Light with LDR
Engineers! I have built a simple airplane strobe light using NE555 and CD4017 in order to flash two LED in a different pattern. I have added an LDR resistor with a transistor in order to switch OFF ...
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Motor Driver Project using 555 Timer PWM + 4N25 + 2N7000
I need to build a circuit that controls the speed of DC Motor using external potentiometer, here are the requirements of the project:
Power source: two 12V dc, 450mA power supplies
Motor: R140 Micro ...
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How to boost the output voltage of my 555 timer design?
I'm fairly new to the world of electronic design. I'm building an astable 555 timer with the limitation being I can only drive it with a 3v coin cell battery (design has to be lightweight). I've been ...
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555 delay timer before powering PCB with 5 V [closed]
I am wanting to know if the circuit below looks correct for using a 555 delay timer to take ~5 secs before applying 5 V to the rest of the board? I'm not sure if I have the correct wiring for it to ...
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555 Timer Astable Multivibrator Circuit Analysis
I was looking at a dead Molex "Suitcase" terminal applicators and found on its controller board this 555 circuit. It appears to be an astable multivibrator, but not the typical kind.
It ...
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NE555 monoflop only trigger once on power
I'm struggling more than I probably should with this simple sounding task:
The bell should be triggered once for about a half or 1 second when 12 VDC are applied.
I tried to solve this with a monoflop ...
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Combining two RC time delay circuits to generate both LOW and HIGH pulses with two push buttons
I have come up with the following circuit that can be used to momentarily generate either a LOW or HIGH pulse based on what push button is pressed.
Can you please tell me if there is any issues with ...
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Monostable mode of ne555 is not working
I am trying to connect a 555 timer in the monostable mode. Although it is a very simple circuit, I still for some reason can't make it work. I would appreciate it very much for your help in this ...
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Monostable "One shot" 555. Longer trigger than T (output pulse width) eliminator
It seemed to me that a classical "one shot" output will go low after a determined period set by T (Output Pulse Width), even if push button is held down. What I want to happen is, when the ...
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Clock logic for 8-bit computer
I have been in the process of remaking Ben Eater's 8-bit-computer, and have a few questions. I got to the part where the clock, which consists of 3x 555 timer, is connected with logic gates. However, ...
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A 555 timer changes time when you touch it?
I designed a simple 555 astable 50% duty cycle square wave generator, assembled in China on SMT PCB. It works well: Except when you touch it, or even put your fingers near it, the timing changes ...
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which mode is 555 timer in this case
This particular timer is made to turn off the load, after KEY1 is pressed long enough. I am not sure if it is in astable or monostable mode.
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Measuring capacitance with NE555 in astable mode
I have one problem with my project. I trying to measure capacitance with NE555, but i have problem with protection.
In this schemeatic instead of a capacitor, I have put connection socket 01x02 for ...
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Correcting error in 555 PWM circuit
I'm trying to design a 555 circuit that outputs a low frequency PWM signal (1-10 Hz) and is adjustable in both frequency and duty cycle (0-100%). I've come across this design and it seems to work ...
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Alternatively blinking two LEDs with 555 Timer
I tried to make a simple 555 timer circuit which turns on one LED when its output is HIGH and turns on another LED when its output is LOW. I tried connecting two LEDs with single 1k ohm resistor (...
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Need 15 minute delay alarm [closed]
I need to use electronics to make a:
12v, ~60db, ~3second intermittent beep, ~15 minute delayed alarm, started by toggle switch, stopped by toggle switch.
Analog or digital, whichever is smaller.
Help ...
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Turn on LED for fix time when box is closed
I have a box which is used to put PCB in it when we are not using PCB. I want to turn on a UV blue LED for 1 minute when box is closed to cleanout the inside of box. I cant use limit switch as I don't ...
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Blue UV LED Timer Circuit
I have designed a PCB for mouth guard device and also its enclosure is ready in which PCB will be placed when its not in use. I want to use a UV blue light for UV sterilization inside the box. Now the ...
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NE555, 50% duty cycle at 110kHz
I want to get an NE555 chip with a 50% duty cycle to 108-110kHz in output.
I have already experimented with various online calculators and values. However, I never get the values that allow me to do ...
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Help with using monostable one-shot multivibrator for limited time
Trying to develop a circuit that would know how to output a square wave with a duty cycle that would be controllable, and the duration would be between half a second and a second.
Now I manage to make ...
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LMC555 delay off timer, M20 motor drive, updated
The goal is to either just give a signal to the motor with momentary switch, or turn on the toggle switch, let 3.7V motor run for a couple of seconds before 440uF is fully charged, after which voltage ...
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How re-trigger NE555 timer in monostable mode while it is already triggered?
While using 555 timer in monostable mode, I want to extend the timer if trigger activates while output is active due to a previous trigger.
For example if I have set the timer for 60 seconds and a ...
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How can I make "50% duty pwm signal" + "flicker signal" circuit? [closed]
I'm new to electrical engineering.
I want to make 50% duty pwm signal(adjustable frequency) + flicker signal as following picture.
I think 50% duty pwm signal can be made using 555 timer like this
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Two 555 Timers working in monostable mode, triggering each other [duplicate]
I'd like to generate a square wave signal with Ton Toff time length based on two analog voltages between 0-5V, went with the method that seems the simplest, two 555 timer ICs with their trigger and ...
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555 timer vs 556 timer
I'm currently working on a project for an internship where I need to reverse engineer a design for a vibration simulator, which use two 556 timers in order to generate four output signals. The final ...
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Rising and Falling edge pulse alternative
I have a requirement to generate a 4 sec pulse when a switch is closed and another pulse when the switch is open with minimal (<10uA) to zero power consumption when the pulses are not being ...
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Replacing pushbutton with sensor in 555 timer latch circuit
I want to make a circuit where there will be a photodiode which when receives infra red light from the IR LED for the first time, produces a high output and when it receives the light for the second ...
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Can’t Get 555 Timer Capacitor to Ever Discharge or Charge to Expected 2/3 Vcc Value
I am trying to set up a circuit in which an NE555 timer's duty rate and frequency
output is illustrated by it's output being connected an NPN transistor. When the out-
put is high, LED1 will ...
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PWM Modulator Circuit
I want to generate a PWM signal from a potentiometer.
This must be a reliable circuit to be placed in a PCB. I've tried a 555 timer circuit in a breadboard (this one), however, the results weren't ...
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555 timer getting power through output pin and powering itself
I'm currently working with a simple 555 variable frecuency aestable circuit, that switches a relay at the desired frecuency.
Here is the schematic so you can understand my issue better:
The circuit ...
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Alterning LED's in breadboard with timer 555, 2 circuits doing the same but i don't understand one of them
I am working on an alternating LED circuit. Initially, I implemented it following the circuit shown below.
From this circuit, I understand that the capacitor discharges from R2 to the discharge pin (...
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555 Timer low duty cycle - wrong start point
I've built a low duty cycle 555 timer (astable) on a breadboard and on Multisim (here).
When the switch is closed, the LED turns on for about 1 sec (1.4 secs in Multisim) then turns off for 50 secs (...
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555 astable resistor location
When looking at example schematics of a 555 astable circuit, they all show the two resistors in series with the C. I'm wondering how this differs from the schematic I've created below;
Here R6 is ...
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Please check if there's anything wrong with my 555 PWM schematic
My first time creating an EAGLE CAD schematic. I want to turn this into a PCB.
I want to ask if there's anything wrong with my schematic, like the wiring or the efficiency or something like that.
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How do I triple the output voltage of a 555 timer boost circuit?
I currently have an output of 160V, but my application requires a minimum of 400V-500V. Is there a method to triple the existing 160V to achieve the desired voltage range of 400V-500V?
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555 Timer: Role of the Discharge Pin in A-Stable Mode
I am trying to build a 555 timer circuit and am stuck on understanding how exactly the discharge pin works. I am going off of these block diagram from the datasheet
RA, RB and C form an RC network in ...
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NE555 delay before turn-on
To implement a delay before turn-on I implemted this circuit and it works as expected.
When I switch on, the led is on after few second as expected. fine. When I switch off, the LED still light few ...
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Why is there a spike in the output of this square wave oscillator I made using a 555 time with 50% duty cycle?
The wave form has a spike, what is causing it?
Would that spike create more harmonics than a waveform without the spike?
Scope shot of waveform:
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How can I get a higher voltage from this boost converter built with an NE555?
I built a boost converter, but it only reaches 130V. I want it to drive a Geiger-Müller tube at about 380V.
Is there any posibility to get that voltage from this circuit?
I changed the coil to a ...
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How do you turn on a NE555 Timer in general?
I have a schematic where I'm using an LM741 op-amp as a voltage comparator when its Vout is HIGH/+Vcc it "allows it to operate the 555 timer" and therefore activates the buzzer, and vice ...
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How can I turn off the 555 IC using MCU GPIO?
This is a simple circuit: PWM motor controller circuit using switch potentiometer
I want to turn the 555 IC on/off. But it didn't work.
How can I fix it?
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Current source should work but doesn't?
I have having issues with these opamp current sources with a current source controlled 555 sawtooth generator.
I have tried all of opamp current sources and they all don't work? If I attach a current ...
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Astable multivibrator 555 circuit not working
I'm a beginner in electronics. I'm trying to follow the below schematic for building an astable 555 circuit. Based on the resistance set on the trimmer potentiometer, the speaker should make sounds of ...
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555 timer with 12 V LED pulsing
I have been making a pulsing LED circuit and I have a 12 V LED strip and a 12v supply. I need bright LEDs for my project but the issue is that my 12 V LEDs don't work because the base of Transistor 1 ...
