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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Simple question (I guess): 555 timer

I want to know if it's possible to have a push button so that when it's activated, it turns on my 9 volts circuit for 10 minutes and then turn it off. Also, I don't want this circuit to consume ...
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51 views

Low power timer circuit for solar tracking

I'm making a solar based device but it needs to be aligned according to sun's position in sky , the whole assembly needs to move around 11 degree/hr. So I was thinking of using a timer circuit (low ...
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85 views

NE555 Flyback Driver MOSFET failiure

simulate this circuit – Schematic created using CircuitLab I made this simple NE555 Flyback driver. I used a 9V Battery to power the NE555 and a 24V 6A power supply to power the flyback. ...
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56 views

Generating PWM from rectified sine wave using 555

I want to generate a PWM signal from a rectified sinus wave similar to the image below using 555 timer IC. I have designed the circuit below for this. I want to get a duty cycle of 80% at the ...
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2answers
94 views

What is the tiniest, low-power, and efficient am transmitter?

Here are my constraints: I need to build an am transmitter, but it has to fit in a 1 inch diameter and ~1 inch height box. Since the box is very small, I plan to use a CR2032 battery, which is also ...
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44 views

555 Timer Astable Multivibrator

Why does the astable mode in 555 timer require two resistors, whereas monostable works with just one resistor ? The cap gets charged through R1 and R2 and gets discharged through R2. But in monostable ...
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31 views

Kaustic Machine's Atari Punk Console: Line Output or Log Pot?

I'm planning to make a atari punk console for an electronics project, but i have a question, the original circuit published here: http://compiler.kaustic.net/machines/apc.html has a "line outout". Is ...
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69 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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64 views

IC555 flyback driver troubleshooting

I made a flyback driver which just uses an astable 555 circuit to drive the flyback. The 4 and the 8 pins were connected to the positive rail. 7 pin was connected to the positive rail via a 1K ...
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3answers
79 views

How to trigger something once a day [duplicate]

What would be the right thing to use if I want the base of a transistor to be high for 12 hours and low for 12 hours? I ask because I would like to make a circuit that regulates temperature in a ...
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1answer
48 views

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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161 views

Using 555 to generate square signal with fixed duty cycle / variable frequency

I am attempting to design a circuit whose output is a square wave with the following properties: Fixed duty cycle, as high as possible (let's say 99%) Variable frequency, between 0.2 - 20 Hz (I'm ...
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49 views

How do I replace a CdS sensor in a circuit with an ALS replacement?

I am wanting to replace a resistor in a 555 circuit with a light sensor, but don't want to use the traditional CdS cell. I'd like to use an ALS such as the Everlight ALS-PDT144-6C/L451. This is the ...
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265 views

555 saw tooth generator diodes purpose?

I'm given this 555 timer based monostable saw-tooth generator. This is a known arrangement for this part. The difference from other circuits I've seen is that the bias network of the external ...
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100 views

Control 12v motor with 5v PWM

I have 5v PWM (555 generated) and I want to control speed of a motor using it. The problem is my motor is 12v and by diving it with a 5v PWM I can't reach full speed of a 12v motor. my pwm generator ...
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101 views

What is the equation for the 555 timer control voltage?

I was just wondering what the equation is to find the 555's output frequency is, when a control voltage is applied to pin 5. That would be very useful for me to know! [Edit By OP] So based on what ...
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77 views

How do I connect a 555 timer to a CMOS Input?

I designed the following circuit, using a 555 timer, to supply a single trigger pulse with the same width to digital circuits, no matter how long the button is pressed. The actual pulse output works ...
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2answers
119 views

Simple frequency deviation to voltage converter

I have a capacitive sensor connected to a 555 timer wired as an astable multivibrator and the free running frequency is 60kHz. When the capacitance of the sensor changes, the frequency of the 555 also ...
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85 views

Toggling on and off 220V power

I have a 9V 555 timer circuit and I want to use it to automatically turn on and off a 220V water pump. What can I use to connect the timer and the pump? Is there like a transformer or something?
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42 views

Random timed output circuit [closed]

I am in need of some help with a project. I am trying to build a circuit that will turn on three LEDs randomly on a 1-5second cycle. I have the basic when it comes to electronics, but get stuck on ...
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1answer
66 views

Power a circuit and read output from tablet microphone port

I have a project that I'm currently powering with a AAA battery, providing 1.5v to a simple 555 timer circuit. The output of the circuit goes through a voltage divider into the microphone input of a ...
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3answers
155 views

Can you make a waveform asymmetrical with the 555 timer?

Using a 555 timer how do we output a biphasic square wave instead of a monophasic? Is there any way to make it asymmetrical? If not are there any other devices or circuits to use to make an asymmetric ...
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3answers
181 views

Control RGB LED without microcontroller

I have an RGB LED that I'd like to change from green to red when a circuit is completed. While I know this is very simple with tools like an Arduino, I'd love to not use a microcontroller. Would it ...
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68 views

555 timer multivibrator charge and discharge

With this kind of connection I expect 555 to run as a multivibrator. As far as I understand the discharge of the capacitor should be via R2, while charge of the capacitor via R3 and D1. => discharge ...
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1answer
114 views

How does a series capacitor affect a square-wave on-off signal?

This question refers to the book Make electronic's experiment 18. I have included a picture below. ...
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75 views

IC 555 timer to provide oscillation for high amp electromagnet

I am using a self-built electromagnet in my project that consumes 9.0 amps at supplied voltage of 12 VDC. I don't mind even if amps goes high. The power supply I am using can provide up to 30 amps. I ...
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196 views

DAC to run a 555 Timer [duplicate]

I am trying to create a PWM signal using a POT from 555 Timer to control speed of a 5V DC motor. I have a development board with a C8051F020 microcontroller, a 100K POT and an LCD display. The ...
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282 views

How to design a binary counter with 4029 binary counter ic

I am trying to build a circuit that counts up to 15 or 1111 in binary using a 4029 ic and 4 LEDs as demonstrated in this video. I have studied the 4029 datasheet, and I still can't figure out how to ...
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109 views

Get ADC value to run external 555 Timer

I am working on Motor speed and position control. The requirements of the project are: 1. Set a speed to run the motor at a particular frequency. 2. Use a potentiometer to set the speed displayed on ...
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2answers
264 views

555 to drive a MOSFET

I wish to drive a MOSFET using a 555. I dont have a driver handy, will it be fine to use a transistor instead? So the output of a 555, could activate a transistor(as swtich), which allows a source to ...
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86 views

Is this circuit a viable implementation? [duplicate]

Following on from an earlier question where the implementation was flawed, can anyone advise if the below is a viable implementation of a circuit to handle a matrix keypad? The idea is that one ...
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2answers
80 views

How can I toggle a astable 555?

I'm using a NE555 running at 37KHz to generate a carrier frequency for transmitting IR. Now I need to modulate it using OOK, I know that are various ways to toggle it. The most obvious way is to ...
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2answers
122 views

How to avoid using relays/analog switches in a musical sequencer?

I'm building this: Albeit with a single pulse adding a bit to the shift register when the circuit is powered and another 555 timer (I'll probably use a 556 for both) to provide the clock for the ...
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1answer
80 views

Holding voltage high, for monostable 555 timer pulse

First I'll mention I am an amatuer in electronics and therefore I ask for easy to implement answers. Thanks. Straight forward to my question: I want to know if there is a simple (and cheap) way to ...
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1answer
79 views

Alternative to TPST Shift Registers?

So I'm building a musical sequencer that uses a shift register to close relays and pass the discharge pins of three 555 timers through a manual switch and potentiometer (acting as a variable resistor) ...
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2answers
114 views

Adjustable 555 timer off duty delay

What I want to do is have a circuit with a 555 timer (which is what I have available) that works the opposite of what a monostable circuit should do—well, kind of. What I mean is, on a regular ...
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2answers
185 views

555 Timer with a 50% duty cycle

I'm trying to build a 555 timer with a 50% duty cycle. I followed the instructions given here (pg 12). I used a 470 microfarad capacitor, 150 ohm resistor and a kohm resistor. The output voltage is ...
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1answer
115 views

variable 555 circuit with equal LOW&HIGH frequency

I've started to play with the 555 chip. There is a lot of documentation out there. So I want to create a strobe light project, with an adjustable frequency. I've played with a lot of capacitors (1nf, ...
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90 views

Constant Sum Voltage Divider With Thermistor/Temp Sensor

I need a circuit with a thermistor/temp sensor that will essentially emulate a pot. In other words, I need a voltage divider that varies with the resistance of the thermistor/sensor, but keeps the ...
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347 views

How long can a 555 be run on a 9V battery?

Is there a way to figure how long can a 555 run on battery, when reset is grounded, to have no output?
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312 views

555 Temperature Controlled PWM

I am trying to build a temperature controlled 555 circuit to drive a cpu fan (used for cooling my entertainment center) I built this using slightly different diodes and MOSFET, and it works great ...
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201 views

LED Blinking with 555 on button press

This may be a simple question, but I couldn't find anything exactly for this. I wish to implement LED blinking if a button is pressed, and it should continue to blink, unless button is pressed again. ...
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1answer
148 views

555 timer - Creating a 5 second astable pulse

I need to a clock pulse where each pulse last 5 seconds for a traffic light controlling system assignment. I haven't worked with the 555 timer much and I haven't had any success with this. I used the ...
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3answers
131 views

Limit Number Of Pulses From 555 Or Similar

I need as small a circuit as possible that can produce 2 pulses (say maybe 200 milliseconds long and apart) when I press a button. My thought was to use a 555 timer and set it up for my desired pulse ...
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166 views

What is the typical frequency drift of an astable 555 circuit over its lifetime?

I am involved in qualifying a sine wave generator that is using a first order LPF and a 555 timer in astable configuration to generate a sine wave(-ish) output. I would have designed it differently, ...
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312 views

Simple Ray gun sound - buzzer

I am trying to put together a ray gun wrist gauntlet for my son's Buzz Lightyear Halloween costume. I think am going to do a little circuit with a big red LED and a 555 timer to make it flash (maybe a ...
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3answers
131 views

555 Timer Triggering Too Easily

I've got a 555 timer being powered by a 5v rail that is isolated from the 3v rail running a motor driver, which runs a motor. The 555 is only supposed to fire when it gets the signal from a 38khz ...
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464 views

How to reset a 4026 counter IC when it reaches 6 for electronic dice

I'm trying to build a circuit to simulate a dice roll using a 555 in astable as it's heart. The output pulses are counted by a 4026 and then fed into a 4511 BCD to 7 segment decoder. It works ...
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191 views

Can you use a 555 to modulate a laser

Will I be able to modulate a 1mW laser using a 555 timer LED circuit by replacing the LED with the laser diode?
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950 views

Need help with 90vdc PM motor speed control circuit

I recently found a Permanent Magnet 90vdc motor, 2.5hp, 18Amps. It has simply two wires for voltage (red/black) and two for thermal breaker circuit i believe (blue/blue). It came out of an old ...