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555 Timers - random on / off time

 
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Davros



Joined: 26 Jun 2004
Posts: 2


Post05 Aug 2004 13:03   555 Timers - random on / off time

I think I have seen somewhere how you can use two 555 timers to make a variable output that makes the high and low times constantly different.

Think it linked the output of one to the input of the other.

Anyone have a schematic / site with this onfo or is there another way to do it?


Thanks
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cherrytart



Joined: 26 Feb 2002
Posts: 125
Helped: 5
Location: oklahoma


Post07 Aug 2004 6:16   555 Timers - random on / off time

Walter Jung had an IC Timer Cookbook years ago. I've never seen it online.

National Semiconductor used to have lots of 555 uses in their data book.

If you want variable timing out of the 555 you have to connect a variable signal to the Control Voltage input (or else use non-linear components, like an incandescent lightbulb for a charge or discharge resistor). And the only place to get a varying signal (that is, an analog varying signal) is at the timing capacitor.

So my guess is that you build two monostables and connect their Control Voltage input to the other timers timing capacitor.

Wackiness ensues.
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cherrytart



Joined: 26 Feb 2002
Posts: 125
Helped: 5
Location: oklahoma


Post07 Aug 2004 6:26   555 Timers - random on / off time

ooops! not monostable, two astable multivibrators is what i meant
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suru



Joined: 31 Aug 2007
Posts: 161
Helped: 4


Post25 Sep 2007 11:35   555 Timers - random on / off time

REFER OPAMP BY GAIKWAD
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shiveshdubey



Joined: 13 Sep 2007
Posts: 24
Location: India


Post11 Oct 2007 13:11   Re: 555 Timers - random on / off time

Davros wrote:
I think I have seen somewhere how you can use two 555 timers to make a variable output that makes the high and low times constantly different.

Think it linked the output of one to the input of the other.

Anyone have a schematic / site with this onfo or is there another way to do it?


Thanks

there is a lot of resources available on net itself regarding 555 and its applications.
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