Timer help.... - Electronic Circuits Projects Diagrams Free

Rescue1 · 12th February 2004, 04:36 AM

Hello everyone.I would like to make a simple circuit that will give a pulse approx. 2-5 seconds after it is powered up,or triggered.Now a 555 can be set up in monostable as we all know,but it will give a pulse as soon as it is triggered.I can't see a way to do this with a 555,so maybe someone has a suggestion on maybe another chip.Thank you for the help,this site is great..... :P

tavib · 12th February 2004, 05:43 AM

:P
One way is to use 2 monostables, one for delay, output of this will trigger the second for generate pulse.
One chip with 2 monostables is CD4098, search on net for it description.
But the output of 4098, like other CMOS 4xxx, drive a small currrent on output(depending of voltage), so if you need more current a transistor must be inserted on output.

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12th February 2004, 04:36 AM	(permalink)
Rescue1	Timer help.... Hello everyone.I would like to make a simple circuit that will give a pulse approx. 2-5 seconds after it is powered up,or triggered.Now a 555 can be set up in monostable as we all know,but it will give a pulse as soon as it is triggered.I can't see a way to do this with a 555,so maybe someone has a suggestion on maybe another chip.Thank you for the help,this site is great..... :P

12th February 2004, 05:43 AM	(permalink)
tavib	:P One way is to use 2 monostables, one for delay, output of this will trigger the second for generate pulse. One chip with 2 monostables is CD4098, search on net for it description. But the output of 4098, like other CMOS 4xxx, drive a small currrent on output(depending of voltage), so if you need more current a transistor must be inserted on output.