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Delayed power / flip circuit help

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markponikvar

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Here is what I am trying to do:

The +12VDC can be switched on or off.

If the +12VDC is off, then output 1 and output 2 should be 0.

If the +12VDC is turned on, output 2 puts out +12VDC, and output 1 is 0. Around 20 seconds later, they switch, so that output 2 goes to 0 and output 1 goes to +12VDC.


R1 = 19 turn 1K pot (used for changing the timing delay for the switchover, not sure if 1K is the correct value)

D1 = 1N4002, should cause a 0.7V drop or so.

C1 = electrolytic cap (+ up, couldn't find the right symbol), 2000uF 25VDC

Q1 = transistor (no clue which one to use)

U1A = bus (no clue which one to use)


Only additional caviat are that the outputs will each need to be able to drive a relay. I am not sure what else I would need after this.

Thanks for all the help... been over 10 years since I played with circuit design :(

Mark
 

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