555 Timer example

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

Attachments

• 38.1 KB Views: 8

jpanhalt

Joined Jan 18, 2008
11,087
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

King7

Joined May 14, 2016
31
ahhh sorry
the frequency is 50

jpanhalt

Joined Jan 18, 2008
11,087
ahh sorry
Are you interested in getting help to solve the problem?

John

King7

Joined May 14, 2016
31
yup brother

bertus

Joined Apr 5, 2008
22,277
Hello,

The frequency is 50 what? Hz,kHz?

Bertus

King7

Joined May 14, 2016
31
Hi bertus
it's 50 Hz

jpanhalt

Joined Jan 18, 2008
11,087
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
22,277
Hello,

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

Bertus

King7

Joined May 14, 2016
31
which capacity i shall use
c1 or c2 ?
or both

Alec_t

Joined Sep 17, 2013
14,313
Just C1.

King7

Joined May 14, 2016
31

King7

Joined May 14, 2016
31
Hello,

View attachment 106064

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

Bertus
Hey bertus man
which capacity i shall use
c1 or c2 ?
or both

bertus

Joined Apr 5, 2008
22,277
Hello,

C1 is the timing capacitor,
C2 is for decoupling.

Bertus

King7

Joined May 14, 2016
31
Hello,

C1 is the timing capacitor,
C2 is for decoupling.

Bertus
so it's C1 then just like alec said
thanks bro

bertus

Joined Apr 5, 2008
22,277
Hello,

What is the total period time, when the given frequency is 50Hz?

Bertus

King7

Joined May 14, 2016
31
Hello,

What is the total period time, when the given frequency is 50Hz?

Bertus
i got the result (0.160 s) so it will be (160 ms)

jpanhalt

Joined Jan 18, 2008
11,087
That is not correct.

John

King7

Joined May 14, 2016
31
This is my calculation

Attachments

• 83 KB Views: 8

jpanhalt

Joined Jan 18, 2008
11,087
That also is not correct.