Auto polarity changer

Sep 11, 2007 9 Replies

I need a circuit to automatically change output from a high to low, every time I remove power. How about like a 555 chip or some type of flip/flop that gives you a high output when triggered when you first apply power? After you shut the system off and turn it back on the output is low. Next time power off then when back on, the output of the chip is high. IOW alternate highs & lows each time the system is turn on. I hope my explanation is OK.



Bill


"Bill" wrote in news:ABqFi.5929$d01.1853@trnddc08:

4013 with 9v cell, a few AAs, or a lithium cell to continually power the 4013.

PIC12Fxxx (with EEPROM), a couple of TO-92s or 3-pin SMT devices (regulator and reset), a bypass cap, and a MOSFET/diode to drive a DPDT relay. 6 parts, thru-hole if you like. You would also need to write a (very) small program.

Best regards, Spehro Pefhany

"it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

"Bill"

** Hey f****it.

Your Q requires the device to have a ** memory ** .

Simple enough with a mechanical switch or similar.

But ONLY a permanently powered electronic device or one fitted with special non-volatile memory can do that pony trick.

Get real - you PITA wanker.

..... Phil

Posted so far I think was: uC with mem (ex: flash mem) logic + battery

Here's my short term idea...CMOS logic + Supercap!

D from BC

But when you read a lot of science fiction anything is possible. You specialistic nerds just need to tell him how to do it!

I thought we had a new rule here: No "use a PIC" posts without a full schematic, code, and link to the development system. ;-)

Thanks! Rich

Sure, and no ASCII schematics without complete parts lists, sources with price and availability, and worst-case calculations for tolerance, temperature variations and MTBF of every part.

Best regards, Spehro Pefhany

"it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

All PICs are CMOS,but not all CMOS is PIC.

"Spehro Pefhany"

** Asinine false analogy.

Grow up, pedant.

....... Phil

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