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2684 Views 1 Reply Latest reply: Jun 10, 2014 10:12 AM by mrtibbs RSS
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Jun 9, 2014 10:09 PM

Time Delay for controlling a 12V Bulb

I'm helping a friend with a prop that he is working on. Basically what we just need to do is to control the duration of a 12V bulb. The bulb wll be turned On and after a few moments it should automatically turn Off. The thing is we are not sure yet, or rather, the duration of the delay is not set, we might need to adjust as duration in the future.

 

I'm thinking this might be a simple project, could anyone help me on how to go about this project. Many thanks!

  • mrtibbs Novice 13 posts since
    May 21, 2014
    Currently Being Moderated
    Jun 10, 2014 10:12 AM (in response to Riley)
    Time Delay for controlling a 12V Bulb

    The simplest way to do this, is to set up a basic RC circuit.  Use a varying load resistor to control the resistance which will then control the disipation of charge from the capacitor.  This will allow you to adjust the time in which the bulb goes out (albiet dim out).  If you need it to abbruptly turn-off after a given time, you can also use a series of diodes to regulate a cutt-off voltage, this will abruptly turn-off the bulb when the given threshold voltage is no longer met.

     

    Finally, you can use a microcontroller to do this fairly easily.  Just depends on what you have lying around.

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