Long Time Delay (4-6Hrs) from low supply - Electronic Circuits Projects Diagrams Free

DavidND · 19th September 2003, 12:23 AM

Hi all

. Sure hope you can help

I need a cct to turn off up to 10 LEDS after 4-6 hrs but I need to do it from a supply that could range from 5v down to 3.5v. The dear old 555 doesn't seem able and someone recommended a ZN1034 but I cannot find anything about it that's current.

Has anyone any suggestions please? :?

Dave

Sebi · 19th September 2003, 06:58 AM

Use CD4541 counter-type programmable timer.

DavidND · 19th September 2003, 05:08 PM

Sebi

I found a data sheet and it looks the right thing alright. DO you know of a cct I could use please

Dave

DavidND · 19th September 2003, 05:26 PM

Sebi

A question. Does this chip need an external clock? If so it would make it phisically too big. The time accuracy doesn't have to be 100% accurate. + or- 5 mins is fine.

Thanx

Dave

Sebi · 19th September 2003, 06:45 PM

This IC contains an internal oscillator (need external R(poti) and C) and a programmable divider. I've tryed to find my old design, but no luck...)
In my design (the big advantage of IC) i can adjust the long time in few minutes: i put a jumper the low divider position, set the the time with poti, and thereafter put the jumper to high divider position.

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19th September 2003, 12:23 AM	(permalink)
DavidND	Long Time Delay (4-6Hrs) from low supply Hi all . Sure hope you can help I need a cct to turn off up to 10 LEDS after 4-6 hrs but I need to do it from a supply that could range from 5v down to 3.5v. The dear old 555 doesn't seem able and someone recommended a ZN1034 but I cannot find anything about it that's current. Has anyone any suggestions please? :? Dave

19th September 2003, 06:58 AM	(permalink)
Sebi	Use CD4541 counter-type programmable timer.

19th September 2003, 05:08 PM	(permalink)
DavidND	Sebi I found a data sheet and it looks the right thing alright. DO you know of a cct I could use please Dave

19th September 2003, 05:26 PM	(permalink)
DavidND	Sebi A question. Does this chip need an external clock? If so it would make it phisically too big. The time accuracy doesn't have to be 100% accurate. + or- 5 mins is fine. Thanx Dave

19th September 2003, 06:45 PM	(permalink)
Sebi	This IC contains an internal oscillator (need external R(poti) and C) and a programmable divider. I've tryed to find my old design, but no luck...) In my design (the big advantage of IC) i can adjust the long time in few minutes: i put a jumper the low divider position, set the the time with poti, and thereafter put the jumper to high divider position.