LED is not flashing using 555

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popkutty

New Member

• Nov 19, 2011

• #1

I've used the circuit of https://3.bp.blogspot.com/_RpOfkmvm...dlFi0/s1600/555+timer+bi-stable+operation.jpg

R1=1K
R2=10K
C=100uF.

It's continuesly output is High. It's not flashing. I gave 4.5V as Vcc.
What's the problem for this?

 

ericgibbs

Well-Known Member

Most Helpful Member

• Nov 20, 2011

• #2

hi,
It could be any number of problems, eg:
The 100uF polarity is reversed.
The 555 is incorrectly wired, etc

Please post a clear picture of the project so that we can check your connections.

 

orbiter

New Member

• Nov 20, 2011

• #3

Check the GND on pin 1?

 

Last edited: Nov 20, 2011

4pyros

Well-Known Member

Most Helpful Member

• Nov 20, 2011

• #4

You may need more than 4.5 volts supply, thats right at the min spec. Try 5 volts.

 

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popkutty

New Member

• Nov 20, 2011

• #5

https://www.facebook.com/photo.php?...103378739834.2015712.1087701578&type=1&ref=nf

Here is my circuit Mr. Eric Please check and say...

 

ericgibbs

Well-Known Member

Most Helpful Member

• Nov 21, 2011

• #6

popkutty said:

https://www.facebook.com/photo.php?...103378739834.2015712.1087701578&type=1&ref=nf

Here is my circuit Mr. Eric Please check and say...

Click to expand...

hi,
Checked your circuit photo, its wired all wrong, its possible that the 555 is now damaged.

I will post you a new circuit later.

This image is the circuit you posted.

 

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Last edited: Nov 21, 2011

Boncuk

New Member

• Nov 21, 2011

• #7

I have simulated the original circuit and it works like a charm.

Check your pin count. Something is very wrong with it.

IC pin count starts at pin1. Left hand bottom pin and follows to the max pin number in an anticlockwise pattern.

So if pin1 is at left hand bottom pin8 must be at left hand top.

You obviously fried your chip. Time to use another one and do it right this time.

Boncuk

 

4pyros

Well-Known Member

Most Helpful Member

• Nov 21, 2011

• #8

Looks like the pins on the right hand side are wired upside down. Power should go to pin 8 not 5. You should put a cap on pin 5.
Andy

 

ericgibbs

Well-Known Member

Most Helpful Member

• Nov 21, 2011

• #9

hi,
Try this very simple layout, as I said earlier the 555 maybe faulty.!

 

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popkutty

New Member

• Nov 21, 2011

• #10

Oh god. Thank you Eric and Boncuk. I were wrong in pin Count. I'm very beginner to Electronics, Thank you Eric for the Circuit...

 

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popkutty

New Member

• Nov 21, 2011

• #11

Can you please tell me, from which software I can simulate electronic circuits.?

 

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popkutty

New Member

• Nov 21, 2011

• #12

Thank god. My IC is not damaged. Maybe I gave only 3V for wrong connection. Thank you Eric, The circuit you gave i used. It's working. I happily finished my first project... Huhuhu...!

 

ericgibbs

Well-Known Member

Most Helpful Member

• Nov 21, 2011

• #13

popkutty said:

Can you please tell me, from which software I can simulate electronic circuits.?

Click to expand...

hi,
Well done.!
Look thru these free sims.
https://www.google.co.uk/search?q=e...s=org.mozilla:en-GB:official&client=firefox-a

 

4pyros

Well-Known Member

Most Helpful Member

• Nov 21, 2011

• #14

Thats awesome. You now have the bug!

 

DerStrom8

Super Moderator

• Nov 21, 2011

• #15

Alas, he was unable to witness the true power of the magic smoke, but I am glad he got the circuit working

 

Last edited: Nov 21, 2011

Ziddik

Member

• Nov 21, 2011

• #16

i see magic smoke everyday lol

 

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popkutty

New Member

• Nov 22, 2011

• #17

Hey guys, I found one thing, I did Monostable from 555 and I just touch the Triger, it turns on the LED, I continuesly touch the Trigger what a magic..! The monostable working as astable, LED is blinking, how's it possible...?

 

4pyros

Well-Known Member

Most Helpful Member

• Nov 22, 2011

• #18

Keep your finger off it. You keep trigering it.

 

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popkutty

New Member

• Nov 22, 2011

• #19

Ya, how's it happening.? By this, we can do touch sensor I think...

 

4pyros

Well-Known Member

Most Helpful Member

• Nov 22, 2011

• #20

Your skin can effect sensitive circuits.