555 timer

Follow this tutorial regarding timer calculation of 555

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

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.

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.

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.