Two Stupid Questions - Electronic Circuits Projects Diagrams Free

captainkirksdog · 2nd October 2003, 02:48 AM

Hi,
I need answers to these two stupid questions:

#1-How can I use a CMOS-level output (logic HI) to trigger a 555 timer for 1 hour (delay), which in turn triggers another 555 timer for 1 minute (alarm)? (Circuit needed!)

#2-Does anyone have a non-rechargeable battery-backup circuit for 12-volts? Back-up MUST occur within 40 nS of AC Mains failure. Injection time is based on 74AHCT00 series CMOS requirements.

Thanks.

p.s. Please forgive me for double-posting, but I need more help.

tansis · 2nd October 2003, 07:14 PM

the web has more than one web site with a javascript simulator for the 555 timer any good search should turn one up, as for battery backup what's wrong with with with a battery / diode on the supply rail?

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2nd October 2003, 02:48 AM	(permalink)
captainkirksdog	Two Stupid Questions Hi, I need answers to these two stupid questions: #1-How can I use a CMOS-level output (logic HI) to trigger a 555 timer for 1 hour (delay), which in turn triggers another 555 timer for 1 minute (alarm)? (Circuit needed!) #2-Does anyone have a non-rechargeable battery-backup circuit for 12-volts? Back-up MUST occur within 40 nS of AC Mains failure. Injection time is based on 74AHCT00 series CMOS requirements. Thanks. p.s. Please forgive me for double-posting, but I need more help. __________________ <ckd> "Chance favors the prepared mind."--Louis Pasteur (1822 - 1895)

2nd October 2003, 07:14 PM	(permalink)
tansis	the web has more than one web site with a javascript simulator for the 555 timer any good search should turn one up, as for battery backup what's wrong with with with a battery / diode on the supply rail?