# 555 timer

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Joined: Mar 29, 2020

Replies: 0
555 timer
March 29, 2020 - 10:11pm

I need to use a 555 timer (astable) mode to keep a LED off for 60 seconds than on for 2 seconds, a bit smoke detectors that turns a red LED on about every 60 seconds for 1-2 seconds then repeats. If it is easier to turn the LED on for 60 seconds and off for 2 seconds it won't be problem as I can invert pin 3 from the 555. I'm using a breadboard. a circuit diagram would be greatly appreciated.

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Joined: Aug 22, 2019

Replies: 124

Follow this tutorial regarding timer calculation of 555

https://circuitdigest.com/article/555-timer-ic

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Joined: Nov 07, 2019

Replies: 122

The 555 timer IC is an integrated circuit used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element. Derivatives provide two or four timing circuits in one package.
the 555 is still in widespread use due to its low price, ease of use, and stability. It is now made by many companies in the original bipolar and in low-power CMOS technologies. As of 2003, it was estimated that 1 billion units were manufactured every year.The 555 is the most popular integrated circuit ever manufactured.

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Joined: Apr 09, 2020

Replies: 55

As this 8-pin IC looks just like a simple component but has multiple features. Only if we talk about its modes of operations, we have 3 modes of operations of this IC. As about your query, for generating a signal having a specific time to turn ON the output and turn it OFF. In a-stable mode, there will be self-triggering, as there is no need of trigger to enable or disable the output. Here the output signals can be determined by the three components used, two of them are the fixed value resistors and one is the capacitor. Here the formula used for calculation of signal frequency is (1.44)/ ((R1+2R2)*C1) and similarly to calculate the duty cycle, ((R1+R2)*100)/ (R1+2*R2). You can also use any respective mobile application available for 555 timer calculations, but the concept to calculate the signal characteristics are same. Here I would like to recommend you to visit SSLA platform, from where you can get further assistance about your project from their technical support team.

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Joined: May 23, 2020

Replies: 48

As this 8-pin IC looks just like a simple component but has multiple features. Only if we talk about its modes of operations, we have 3 modes of operations of this IC. As about your query, for generating a signal having a specific time to turn ON the output and turn it OFF. In a-stable mode, there will be self-triggering, as there is no need for a trigger to enable or disable the output. Here the output signals can be determined by the three components used, two of them are the fixed value resistors and one is the capacitor. Here the formula used for calculation of signal frequency is (1.44)/ ((R1+2R2)*C1) and similarly to calculate the duty cycle, ((R1+R2)*100)/ (R1+2*R2). You can also use any respective mobile application available for 555 timer calculations, but the concept to calculate the signal characteristics are the same. Here I would like to recommend you to visit Sierra Software Ltd. platform, from where you can get further assistance about your project from their technical support team.