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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Adding a sensor to a traffic light circuit?

I am using the current circuit to time a basic traffic light that changes every twenty seconds: However, I've been trying to figure out a way to add a way to detect a car stopping at the light, so ...
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2answers
43 views

Resistors and capacitors calculation for 555 timer circuit

I am new to electronics and I want to try an experiment. I want to use a 555 timer to create an automatic food dispenser for my aquarium (something like opening a small door when the timer has ...
6
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1answer
182 views

Trouble getting 555 timer IC circuit to work properly (Make Electronics Book Experiment 18)

I am currently reading a book titled “Make: Electronics”. This is an electronics book whose target audience is supposed to be complete beginners. One of the book exercises (Experiment 18) includes a ...
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2answers
21 views

555 Timer Min Max Expected Output Voltage Value

Could someone please tell me what are the min and max output values that should be expected from a 555 timer Output (pin 3) given X volts as the voltage source? For example, assuming that the 555 ...
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2answers
67 views

How to control on/off with multiple LEDs without traditional multiplexing

first post here but I've been doing some research and cant find a definitive answer. Goal: Use some type of voltage-controlled switches in parallel (similar to schmitt trigger) that will accept PWM ...
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3answers
63 views

How do I use pin5 to control duty cycle of a 555 based PWM?

I have built a simple PWM using a 555 IC to drive a motor for an optical chopper and I want to be able to use the output of the chopper signal as a speed correction feedback for the PWM. I think I ...
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3answers
95 views

Can an eight ohm speaker produce ultrasonic sound?

I am currently making an ultrasonic dog repellent circuit using a 555 in astable configuration generating a frequency of 30khz. Most circuits that I saw use a piezo buffer. I was thinking that since a ...
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0answers
33 views

How to control direction AC motor with 555(clockwise-off 5sec-anticlockwise)

How do I control an AC motor direction with a 555 timer monostable delay configuration and a few relays.The nature I want it to be is anticlockwise all the way(with a press of a button) then press ...
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2answers
89 views

Periodically reset microcontroller

I have a tiny embedded system build around a Holtek HT48F06 microcontroller to monitor RFID tags (RDM630). Unfortunately it only detects the arrival, not the removal of a tag. As a workaround, I want ...
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0answers
51 views

How to calculate the Ra and Rb values for the desired frequency and duty cycle?

I am designing a DC-DC boost converter for Vin = 5V to Vout = 15V. To generate gate pulses, I will be using a NE555P Timer by TI - ...
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1answer
49 views

Driving MOSFET with 555 timer [duplicate]

I am building a plasma speaker using a 555 timer to generate the audio tone. I am driving a mosfet with the output of the 555 timer, which in turn powers a flyback transformer to generate a plasma ...
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30 views

circuit for switching on and producing desired high pulse then circuit turn off without using micro controller

i have no prior knowledge about electronics , but i am trying to make a circuit that turns on the switch after 10 seconds and then produce a desired length high pulse say 30 seconds then it turn off ...
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1answer
28 views

Problem in Proteus With 555 monostable trigger

I try to make a MonoStable in proteus. Below is my circuit: But my output pulse width is dependent on the trigger circuit. For example in the above circuit according to the formula $$T=1.1RC$$ I ...
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1answer
53 views

Simulation error and output voltage drop of DC voltage doubler circuit in Multisim

I have simulated the circuit provided in this link:http://www.circuitdiagram.org/dc-voltage-doubler-multiplier-circuit.html. But, when I simulate the circuit, the output voltage is dropped and I get a ...
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0answers
36 views

Problem with timer and capacitor circuit, Repeater

I am Trying to make a circuit in which I am using 2 timers 220V AC and set their time to 4sec and 1 capacitor 3.5uF 400V AC. I have removed the timers from their base so you can understand the ...
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3answers
77 views

how to calculate time for timer relay

In the below circuit of Timer Relay, how I can calculate the time for C1 to be fully charged? please don't use regulator, transistor or any other device I just want to use Resistance and want to ...
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3answers
83 views

Sawtooth generator adjustable from 100MHz-500MHz

I need an easy circuit that will generate sawtooth waves at adjustable 100MHz-500MHz (preferably set by a resistor) from 0V going up to 5V. The waves themselves does not have to be perfectly linear, ...
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2answers
78 views

555 as a Digital Coupler

I want to read MIDI data with an arduino (specifically an ATtiny85) for use in a synthesizer. The only method I'm aware of involves using an optocoupler such as the 6N138 found on this Instructable. ...
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1answer
158 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
75 views

Dimming an LED Strip (9v) with a 555 timer and MOSFET

I'm doing some VERY amateur prop building for an upcoming night of cosplay and I'm trying to create a throbbing/pulsing crystal for the top of a magic staff. Initially, I was just going to use a ...
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2answers
87 views

Best way to sync LED's to light NES figures on a wall clock?

Advice & Ideas needed... Working on a project - a custom wall clock with perler bead NES sprites in the place of the numbers. The figures are mounted to a wood board with cutouts underneath, and ...
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0answers
56 views

Measure frequency of a 555 timer with multimeter

My multimeter has a frequency option so as the manual says I connect the COM and V, the thing is I have no idea where to connect the leads to my 555 timer circuit so that I can measure it's output ...
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1answer
61 views

555 timer accident

I accidently applied around 5V to the output pin of the 555 timer.The output is zero when I ground the trigger, and an LED connected between 5V and pin 7 will not respond when 5V is applied to the ...
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1answer
57 views

Variable Timer Circuit w/ Digital Display for Counting Down

I would like to make a timer. The timer will have a 7 segment digital display and will work with a microcontroller of some sort. I would like to be able to put in a time (e.g. anywhere between 0 - ...
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1answer
87 views

Can I alter this circuit?

I am making the following solar charge controller circuit based off of the NE555: This is the webpage I got the schematic from: http://mdpub.com/555Controller/ The potentiometers at the trigger ...
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1answer
69 views

help with 555 timer to dim led driver

I am trying to build some DIY LED fixtures to light my saltwater aquarium. They need to be dimmable, and I want to dim them with Pots for convenience versus a controller. It will probably be clear by ...
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1answer
80 views

555 Timer Zapper

I want to make a simple bug zapper. I was planning to make a cockroach zapper but I want it to be a small DC application and dont have any transformers on hand so I may have to settle for a zapper the ...
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2answers
94 views

How delay or phase shift a signal?

I'm using a 555 to create a throbbing effect on a LED, like in this project. Is there a simple way to delay the signal for a second (then third, then forth...) LED to have them fade in and out at ...
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0answers
33 views

Confirm my suspicions about astable 555 “always on”, dumb mistake?

got a astable 555 timer schematic here, worked fine with a through hole NE555P when I didn't add the switch to pin 4. Now, in my SMD NE555PSR, the pulse is simply always 'high' or always 'low'. Am ...
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1answer
122 views

555 timer as FM transmitter vs. Tank Circuit

This site seems to suggest the use of the 555 timer in astable mode to generate frequency modulation from a source. The typical transmitter uses a tank circuit with an inductor and trimmer capacitor ...
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2answers
41 views

555 timer control voltage

I'm trying connect the 555 timer as a pulse wave modulator. Notice from the diagram below, the - input of Comp1 is internally connected to \$2/3V_{CC}\$. The control voltage is applied at pin 5. The ...
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1answer
101 views

Damped RLC Circuit Equation

I'm trying to measure the inductance of a toroid with the use of a 555 in astable mode. Hopefully, by putting the toroid in parallel with a known capacitor and driving the circuit with a low duty ...
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1answer
137 views

Problem in Basic 555 Timer Circuit

I am trying to build a simple LED flasher circuit using 555 timer IC. Tried building it on breadboard and simulators several times but that is not working. As I am a beginner I think I am making some ...
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0answers
77 views

DC Motor Speed Control With 555

Can you please explain why this circut is not working in simulation. I get GMIN Stepping failed, too many iterations errors. Is there something wrong with the design?
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0answers
40 views

555 trigger with small voltage

I'm trying to determine the right kind of circuit for this situation. I've got a small sensor that goes high whenever a fin passes by a small light and blocks the light. The frequency is about 10 Hz ...
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3answers
127 views

Any way to create a 3 LED chaser with only a 555 IC?

I've seen single and dual blinking circuits, but wanted to know if there was some easy way to squeeze in a third? I don't have a 4017 IC at the moment, unfortunately.
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4answers
694 views

Multiplexing a Circuit

Frankly, I'm overwhelmed with this circuit that I have to start building in lab tomorrow. Last week we built an octal decoder that takes a 3-bit binary input from 000 to 111 and displays a unique ...
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1answer
147 views

Solar Charge Controller Function Details

I am planning to make this controller: I would like to understand the way the components work to switch from charging to dumping and vice versa at set points. Note that the 555 timer is not being ...
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3answers
74 views

Identifying the “Preset” Component in this 555 Monostable Timer PCB

I have a PCB for a 555 monostable timer circuit as shown below: For the most part, the components are clearly labeled (I think the round circle with a + inside denotes a capacitor, but please ...
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2answers
126 views

Difference between NE555 and NE555xx

I'm going to order the NE555 chip from Texas Instruments (Link) to build a circuit, but they only have NE555P, NE555DR etc. Can I use the NE555xx instead of NE555? What is the difference between them? ...
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5answers
440 views

Can someone check over my schematic?

This is the first schematic I have made that was not a simple LED. I want to know if it seems good before I go and build it (and buy the parts). Here is the schematic: Here are a few of my ...
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1answer
89 views

555 and output amplifer with different Vcc supplies

I want to increase the power of the push-pull amplifier in this circuit. The left 555 generates a square wave and the righthand 555 is triggered by it, and the output of both is amplified by the pairs ...
6
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3answers
1k views

555 timer boost converter doesn't meet spec

I've been messing around with nixie tubes lately which requires a high voltage source (~150V-200V) to turn on. I searched around for a simple high voltage generator and found this circuit which uses ...
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1answer
103 views

Driving 555 control voltage with DAC

I have build a stepped tone generator (aka Atari Punk console) which are 2 555 timers connected together (one 555 is configured as a astable oscillator and drives the second configured as a monostable ...
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2answers
117 views

555 Astable Multivibrator Voltage Spikes

I built a 12V LED dimmer based on (modified from) the circuit below. Essentially I used a TIP31C instead of the Darlington pair, and provide power to 555 with 7805. An oscilloscope gave me the ...
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2answers
374 views

Floating charge pump for high side N-channel MOSFET bias

This question is derived from this one. I'd like to keep gate on for an indefinite period of time (100% Duty cycle) and for that I'd like to use charge pump since idea with relay is not attractive. ...
2
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2answers
414 views

Is this 12 volt LED circuit correct?

I found this "Plant Grow LED light" circuit on the Internet and I wanted to know if: (Please don't feel pressured to answer all my questions. You can just answer a few only if you like.) this is ...
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3answers
131 views

wiring 555 to disconnect itself from electricity

i had idea for a circuit with 555 and here is the IDEA: circuit is stationary somewhere, it is in "passive state" meaning its drawing no current from battery and pin 3 is set low, then someone comes ...
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3answers
179 views

Slightly weird astable oscillator in a 555, where does this capacitor discharge to?

In the 555 datasheet, the cap is usually connected to pin 7 (discharge), but in this circuit, it's not: When the capacitor voltage is >2/3Vcc, output will turn off and current will have no where to ...
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3answers
430 views

Modifications to 555 LED Fade Circuit

I was looking for a circuit to fade an LED on and off using no microcontrollers, and found this nice circuit: http://www.555-timer-circuits.com/up-down-fading-led.html it seems like exactly what I ...