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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938 views

555 timer: how to set values to take an hour

I'm new (and novice) in electronics. I came to seek your knowledge to see if someone can help me with a very basic circuit. It is a 555 chip, which should light a LED (for about 1/2 second) every ...
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2answers
170 views

Why does this circuit keep killing my 555 timers?

I have a 555 timer set up in a standard monostable oscillator configuration. Nothing fancy, no modifications whatsoever. I'm driving it with about 12V. If I trigger the 555 with the ground directly, ...
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1answer
44 views

Analog PWM generator from 0%

I have to prepare easy analog PWM regulator which can operate from 0% (0V). I know that one 555 can't do that... Do you know any circuit that can handle that?
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1answer
41 views

Generate PWM signal based on 555 for Meanwell LDD driver

I am using a Meanwell Led Driver LDD-1000H. It has a single pin for PWM input for dimming. I have seen many sketches using the 555 to dim a LED but in these cases the LED was part of the circuit. How ...
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3answers
103 views

Need help with an LED flash circuit

I joined just because I'm having sort of a dilemma. I need to design a flash circuit for a tiny SMD based project, and I have a way of doing it, but I want to see if I can make it better and I haven't ...
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1answer
60 views

Square Wave input into Transformer

Can a square wave generated using an astable NE555 be used as input of a transformer instead of AC? Say, I generate a square wave of 60Hz using NE555 and a 24V at 6A supply and feed it into a ...
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1answer
47 views

Control duty time and frequency with different potentiometers using one 555 timer

How can I regulate duty time and frequency of 555 timer output with 2 potentiometers?
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2answers
148 views

Use 555 for additional 40KHz PWM in Arduino

I need to transmit infra red signals using IR LED from my Arduino device. The IR signals consist of PWM 40 kHz periods and "silence" periods of various length (typical IR remote signals). I know ...
2
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1answer
70 views

Monostable and Astable 555 Timer

To begin with, I must say this is kind of a "homework" but I tried to do it on my own and I haven't succeed maybe someone can help me out with this matter. We're learning about digital systems, ...
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1answer
53 views

Count number of hours elapsed

It's been a long while since I played with circuits, I'd appreciate a sanity check of the following design; I'm trying to count the number of hours since the reset button was last pressed. Ideally ...
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1answer
103 views

555 timer as a humidity sensor

I want to use a 555 timer to measure humidity using a humidity dependent capacitor which goes from about 300-> 400 pF. This makes the frequency way to high for me to measure. Is there some similar ...
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2answers
121 views

555 as a Schmitt Trigger and an ON delay timer?

I've scoured the internet trying to find this out to no avail. I would like to use a 555 timer to produce a Schmitt trigger with an ON delay of 20-30 seconds. Is this possible? Or will I have to use ...
0
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1answer
91 views

555 timer flashing led circuit

I just have a question about this simple circuit or example: http://www.555-timer-circuits.com/flashing-led.html. I just don't get 1) why do they use 9V battery to power a single red LED light. 2) why ...
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4answers
305 views

I just fried a 555 timer IC and I'm trying to figure out how

I'm very new and just fried my first ic, trying to learn a lesson from it. Here's what I was building: (also here) on the 6v in I used 6 AA batteries that were reading about 7.5v on my meter, was ...
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4answers
323 views

Steering Diodes

What are the "steering diodes" next to the pot for? Source: http://www.youtube.com/watch?v=OXsu29K_Ap4
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3answers
161 views

How to make 7-segment display count up ?

I've connect 7447 decoder and 74193 counter as shown in the picture but I have not used 555 timer yet. Is there any way to test the circuit before using 555 ? I've connected the pins (up and down) ...
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1answer
51 views

How do I enable/disable a running 555 astable oscillator with a control signal?

I am going to control a fan using PWM signal. PWM is generated by a 555 IC. The duty cycle rate of the PWM is controlled by a PTC thermistor. And an NTC thermistor decides when to turn on and off the ...
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2answers
110 views

How can I turn pulsating DC (square wave) from a 555 IC timer into an ac square wave?

I am trying to create build a morse code transmitter. I know that morse code is sent at 500 KHZ so I set my 555 to spit out pulsating DC in a square wave with 9 volt peaks. But I am unsure wether ...
0
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1answer
93 views

Problem in creating one-shot impulse circuit

I am a student in university and I have a problem to be solved. I have to design a circuit that gives just one pulse (not periodic signal) when the 220V source is active. I will give 220V to the ...
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4answers
710 views

How to get more current from 555 timer?

My power supply is filtered regulated 5 volt 500 mA . I am using a 555 in monostable mode to switch the motor on for a certain amount of time after the 555 is trigerred. (The 555 is being trigerred by ...
4
votes
2answers
233 views

CD4029 does not initialize at 0

I am attempting to build a very simple 4 bit counting machine using a CD4029 ic and a 555 timer. I have built my circuit on a breadboard and everything seems to be working perfectly, however on the ...
0
votes
1answer
281 views

How to build a blinking 12V indicator LED light

I attempt to build a blinking circuit using 12V truck light ( like this one: http://www.princessauto.com/pal/en/Tail-Lights/4-in-LED-Stop-Turn-Tail-Light/8126047.p). I have try to build a single LED ...
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0answers
81 views

How to combine a 555 timer and an MC34063

So, I've been at a project for a couple of weeks now, far too long in my opinion. I'm coming down to the final push and my last obstacle is to connect two circuits together to make a Piezo transducer ...
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2answers
59 views

555 delayed after threshold goes above control voltage

I am messing around with some 555s I bought a while back (NE555N from STMicroelectronics) and I'm getting some unexpected behavior. I have a capacitor hooked up to both the trigger and threshold pins ...
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1answer
52 views

555 servo controller “modulation input”?

Exactly as the question says. On the TI 555 Rev. C data sheet, what is the modulation input for the PWM circuit? Also, can I round the resistor and cap. to 10k and .022uf, respectively?
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2answers
478 views

Simple methods for switching a boost converter, to get a stable output voltage?

I've made a boost converter circuit, with a MOSFET as a switch, and a (7)555 timer operating as an astable oscillator, and it's output goes directly to the MOSFETs gate pin. The problem is that the ...
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2answers
141 views

How long will this low duty 555 LED blinker last on batteries?

I know there are many questions about LED blinkers, but I haven't yet found a clear answer for this. I have a 555 circuit blinking a blue led (or three in parallel). I has a low duty cycle (using a ...
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1answer
209 views

Difference between two 12V PWM signals/circuits (PIC and NE555)

I'm trying to understand the difference between two 12V PWM circuits I've build and tried. The PWM signal is intended to control the speed of a motor. Only not in the way you would expect. The motor ...
4
votes
3answers
202 views

Using timer to power on/off a high current circuit

I'm working on a Arduino project that takes measurements from the environment and sends them to a remote server over WiFi. The circuit should be battery powered and I've measured that what I have at ...
3
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1answer
102 views

What is the diode for in this 555 circuit?

Here is a schematic of a 555 setup to create a single shot voltage sawtooth pulse across the capacitor C2. It also outputs a square wave pulse on pin 3. A (reversed biased) Zener diode is used ...
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1answer
178 views

Flyback NE555N driver and mosfet overheat

I have built a small and very simple flyback SMPS based on NE555N IC. The circuit exactly I did built from is shown below: It works nicely for small loads. However I have some issues with it: ...
0
votes
2answers
358 views

Astable 555 timing circuit (0.5 Hz and 50% duty cycle)

I am trying to build a timing circuit to generate a 0.5 Hz 50% duty cycle signal. In other words 1 second on, 1 second off, and so on... I have searched a few places and found the following ...
0
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1answer
87 views

An adapter for disconnecting the current after a particular period of time

I want to prepare an adapter which will discontinue the power supply after a particular period of time. The time period will be provided manually using a switch. The time periods are: continuous ...
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2answers
147 views

IR proximity sensor

I have built an IR proximity sensor using a normal 940nm IR LED, Tsop 4856 kHz IR photodiode. I have used 555 timer to generate pulses to the IR led. the circuit is working correctly as far as I know. ...
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2answers
172 views

What do Capacitors do in a System with a Speaker?

I made a circuit based on a diagram from my physics teacher. The circuit has a 555 chip connected to seven wires that make up a circuit. The circuit includes a photocell resistor that acts as a ...
2
votes
1answer
109 views

Combine 2 circuits to get the best of both? Battery management system

I'm working on a battery management system for 2 12V batteries in series, totalling 24V, and I found this very good blog online with 2 circuits that got me very interested: This one, that got me for ...
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1answer
111 views

Digital Clock Circuit With A Buzzer

I developed a digital clock circuit that simply resembles the function of a stopwatch. The circuit works fine, but I decided to add an extra functionality: A buzz is produced each hour, but I seem to ...
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2answers
185 views

NE555 timer not working - how to identify the element at fault?

background Im a beginner in the field of electonics, and I have been trying to put together a IR remote control / laser tag system using Arduino Nano. I am using a TSOP4840 receiver and a TSAL6100 as ...
0
votes
1answer
132 views

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 ...
0
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1answer
87 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 ...
2
votes
3answers
215 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. ...
2
votes
1answer
228 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 ...
2
votes
2answers
177 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 ...
0
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2answers
92 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 ...
0
votes
1answer
106 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 ...
0
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2answers
188 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
138 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
174 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 ...
3
votes
1answer
75 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 ...
3
votes
3answers
877 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 ...