ok guys, this has in my littmited knowledge gone way over my head.

How can i using digital logic to determin from a 12v source if something is on or off.

Thanks guys

 

i'm not sure what you're asking.
do you want to know if something that is running on 12 V is on or off, using 5V logic levels ??

 

Most CMOS logic can run at up to 20v, so the switching point would be as high as 10v, so I think the answer is yes.

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Hi Guys, and thanks for the replies.

Willib yes i want to check to see if something is running from 12v from diggi logic,

 

what is it that you are trying to do ??

 

Willib, i am trying to get a circuit together that will work my headlight washers, but, i only want the heeadlight washers to work while the headlights are on. so a circuit which will wash my windscreen in daylight and also my headlights at night.

Thanks

Don

 

you could power the circuit from same branch as your headlights. no headlights - no power for the circuit.

 

have you tried using a comparator?

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-=: The best low-priced components to troubleshoot with are the speaker and the LED :=-