Auto polarity changer

[Bill]

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

 

[Eeyore]

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.

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

 

[Tim Dunne]

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 ?

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

 

[Gary Tait]

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

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

 

[Spehro Pefhany]

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

 

[Phil Allison]

"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

 

[D from BC]

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

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

 

[neon]

like the man said no power then what? but if you want use a couple of AND gates output to input as a latch. these guys have a forbiden state so use a cap on one input to condition the latch. good luck.

 

[Fred Bloggs]

"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.

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

 

[Rich Grise]

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 ?

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

 

[Rich Grise]

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

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

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

 

[Spehro Pefhany]

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

 

[John Fields]

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

 

[Phil Allison]

"Spehro Pefhany"

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.

** Asinine false analogy.

Grow up, pedant.




........ Phil