Re: Simple Circuit Design

Hi,

20mA is a bit much for 2 coin cells. YOu could run the led at 5mA and use a
high bright one.

As for the rest of the circuit, it needs more detailed information:
1: When the switch is open (no magnet), what does the led do?
2: When the switch goes closed (magnet added) what does the led do at that
moment?
3: When the switch stays closed, for 2 - 3 minutes what does the led do?
4: When the switch goes open after 3-x minutes, what does the led do?
5: When the switch goes open before 2 minutes are up, what does the led do?
6: When the switch stays closed for indefinete, what does the led do?
7: When the switch goes open and closed again after 3 minutes, what does the
led do?

This could be converted to a truth table.
As it is, it sounds like it is probably a monostable multivibrator also
known as a 'one shot'.


Regards
Bernt

"artbinct" <bauera@xxxxxxx> wrote in message
news:1141183121.296083.112710@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
I would like to know if anyone can help with designing a circuit that
powers an LED using (2) 2032 coin cell batteries (6V). The ON/OFF
function of the LED is controlled by a NO switch (magnetic reed
switch-like the kind used on windows in homes for security systems). I
would like the LED to shut off after about 2-3 minutes if the switch is
left in the NC position. I am not sure how to do this. The less
components the better. Any help would be greatly appreciated.

Thanks

Art



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