555 Timer example

Thread Starter

King7

Joined May 14, 2016
31
Hey guys how are you?
i'm kind of new at this so can anyone please solve this homework for me
and because that R1 is unknown it is the only homework requirement
thanks in advanced :)
 

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jpanhalt

Joined Jan 18, 2008
9,740
What is the actual question? Are you given the target frequency? If not, are you asked to solve R1 as a function of the frequency or the other way around?
Have you attempted the problem?

John
 

jpanhalt

Joined Jan 18, 2008
9,740
Some hints. No one here is supposed to solve it for you.
1) Calculate Tl + Th in seconds (or milliseconds)
2) Then calculate Th with the information given
3) Then calculate R1 from its equation and the known values

John
 

bertus

Joined Apr 5, 2008
20,568
Hello,

Your picture has clear formulas:

king7_555_oscillator.jpg

Use the directions of John to calculate the cycle time and the high and low times.
Then you can calculate R1.

Bertus
 

jpanhalt

Joined Jan 18, 2008
9,740
That also is not correct.
1) Where are your units?
2) Given a frequency of 50 Hz, what is the period? That is all the information your need to calculate it.

Just look at the units. What are the units of frequency? What are the units of period?

John
 
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