555 chips, powering up

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planty

New Member

• Oct 8, 2009

• #1

When you first power up the 555 chip in a small kit , it works straight away, but can you stop the unit from working every time you power up, but it still will work on it's trigger input?

I thought it would be a small cap on pin 2 or 4 but the unit still works when powerd up,
Thanks, David

 

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KMoffett

Well-Known Member

• Oct 8, 2009

• #2

Can you post the schematic?

Ken

 

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planty

New Member

• Oct 9, 2009

• #3

**broken link removed**

this does work fine at the moment, i just dont want it to work when it gets powered up.

 

Last edited: Oct 9, 2009

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KMoffett

Well-Known Member

• Oct 9, 2009

• #4

Sorry, but I can't read the small fuzzy image. Can you convert it to a larger size in a GIF or PNG format. They give better detail with a smaller file size.

Ken

 

audioguru

Well-Known Member

Most Helpful Member

• Oct 9, 2009

• #5

Please attach the schematic here intead of over at Photo-Bucket.

 

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planty

New Member

• Oct 10, 2009

• #6

picture as asked..
I think i have done it;.
also i have put 4700uf cap on the pos and neg just to give me a few extra seconds.
The kit is to close a car roof but i didnt want it closing when you start the car as it can take all the power as start the car then closing the roof.

 

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audioguru

Well-Known Member

Most Helpful Member

• Oct 10, 2009

• #7

The schematic was originally made as a fuzzy JPG file type. Converting it to a different file type does not remove the fuzziness. It should have been made as a very clear GIF or PNG file type in the first place.

 

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BrownOut

Banned

• Oct 10, 2009

• #8

I guess you mean you don't need help, since you have "done it." But if you have problems again, you may use the reset pin ( pin 4 ) to prevent the timer from operating on startup. Just use a capacitor and resistor to apply a short reset pulse until the operating voltage settles.

EDIT: On second thought, you probably want to use a short pulse generated from a logic gate or transistor to reset your timer. (Been reading the turtorial)

 

Last edited: Oct 10, 2009

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planty

New Member

• Oct 10, 2009

• #9

your help is great, i just wondered if there was another way,
Thank you again.