Auto polarity changer

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

 

Here's a little conceptual snag for you. If you're going to *remove* the power,
how is the circuit going to 'remember' which state to start up in each time ?

Graham

 

Google 'impulse relay' for a little conceptual enlightenment. They're used
for duty cycling pumps, compressors and the like. Each powerup reverses and
mechanically latches the state.

Tim

 

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

 

"Bill"


** Hey fuckwit.

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!

 

Mechanical latching relay. When power is applied, it pulls in in state 1.
When power is released, it drops out, flipping the pawl. Then it's
energized again, it pulls in in state 2, and so on.

I don't know how common they are, or how you'd find one other than a
google search, but when I was a kid the reversing button on our toy
train just cut off power for a moment, and the train would back up,
then, interrupt the power again, and it'd go forward again.

Good Luck!
Rich

 

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

 

"Spehro Pefhany"

** Asinine false analogy.

Grow up, pedant.




........ Phil