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5th May 2011, 18:03 #1
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555 timer astable multivibrator
In the following astable multivibrator circuit,
in some books, it is mentioned that the duty cycle id
d=( R1+R2)/(R1+2*R2)
in some other books, it is mentioned
d= R2/(R1+2*R2)
which is correct? which one should i use if i want to design a circuit of particular duty cycle ?
please tell me whether duty cycle is Ton/(Ton+Toff) or Toff/(Ton+Toff)

5th May 2011, 18:03

5th May 2011, 18:09 #2
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Re: 555 timer astable multivibrator
" It is so simple to be happy,
but it is so difficult to be simple"

5th May 2011, 18:14 #3
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Re: 555 timer astable multivibrator
duty cycle is Ton/(Ton+Toff)
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5th May 2011, 18:14

5th May 2011, 18:30 #4
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5th May 2011, 18:30

5th May 2011, 18:52 #5
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Re: 555 timer astable multivibrator
This page has the equations and a calculator
555 Calculator
Also check 555 and 556 Timer Circuits
Alex
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5th May 2011, 18:54 #6
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Re: 555 timer astable multivibrator
which is correct? which one should i use if i want to design a circuit of particular duty cycle ?
please tell me whether duty cycle is Ton/(Ton+Toff) or Toff/(Ton+Toff)
In my opinion, you would define high output as "on" and duty cycle as Ton/(Ton+Toff).
In this case, the first expression applies: d=( R1+R2)/(R1+2*R2)
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5th May 2011, 18:54

5th May 2011, 19:01 #7
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6th May 2011, 05:35 #8
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Re: 555 timer astable multivibrator
Ton/Ton+Toff
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21st May 2011, 06:28 #9
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Re: 555 timer astable multivibrator
duty cycle is ton/(ton+toff)
http://teeblog.blog.com/archives/66/#as Read this for calculations and basic theory

4th July 2011, 08:15 #10
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Re: 555 timer astable multivibrator
you can also try this link for understanding 555 ic as astable multivibrator
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