A refresh question

TmKarren

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I have been looking at the timers.  Oh so many.  What is a simple timer I can make for a refresh?  All that I see are for timing the shutter.  Will one of those single timers work?  What are the C's?  Are they condensors?  Will Marty's timer work?  Do I hook it up like he has it?  Thank you for Your Help!!

Here is a shortcut to his timer..


Thanks Again!!
 

Tinhorn

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TmKarren

There are 2 kinds of timers.  One gets triggered, like the delay between pix timers (& Marty's timer) and the other is like a dog chasing it's tail, it goes off every so many minutes automatically  and is not triggered.

The refresh timer does not get triggered,  here is one that I use with the Original version of JoeD's timer (it don't have a built in refresh)

http://www.nightowl.net/~tinhorn/JoeDRefresh.jpg

I don't know what you're going to do with it but be sure to check out JoeD's or Brian's timer IC's.  They have built in Delay Timers and the refresh pulse, all in one, 8 pin chip.

Tinhorn
 

hamiltoe

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Do a search online for an "astable multivibrator"  It is basically a self repeating pulse generator that will give you the refresh pulse that you are after.  Probably the easiest and most reliable would be to use a 555 timer.  The ones using transistors aren't always guaranteed to work 100% of the time this link will give you more info http://www.4qdtec.com/mvibs.html
Here's a link that shows examples using a 555 timer:  http://webhome.idirect.com/~jadams/electro.../555astable.htm
 

TmKarren

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Thank you.  You two rule!!  I have seen the light.  thanks again..
 

Brian

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TmKarren,

Make sure you use the low power 555 timer if you go that route.  Even the low power version can pull upwards of one milliamp in astable mode.
 

Archilochus

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Hi TMK,
You could also use a 4060B chip instead of a 555 - much lower power consumption and smaller timing caps needed.
You could try the simple timing circuit I made for my "squeaker" at:
http://www.geocities.com/archilochus57

I'd just use one of Brians timer chips though - lots of other great functions available with that!

Archilochus
 


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