"Warren Weber" wrote in message
. ..

"Bill" wrote in message
news:A%1Fi.420$1n1.105@trnddc02...
Anyone know of a way to reverse polarity (9 to 12V DC) each time the
power
is removed? In this gadget I have there is a small 12V supply. When I
turn
the gadget off and then turn it back on, I wish to have the 12V reverse
polarities. For another example, I have a black box with 2 posts, the
top
post is +12v and the bottom post is 0v. I turn the power off and the
next
time I turn the power on, I would like the top post to be 0v & the
bottom
post to be +12v. Is there like a simple flip flop chip or ?? than can
accomplish this task? All comments most appreciated. Thanks in advance.

Bill

James had the right, easy answer.

I agree Warren, if I could do it manually, but I need a circuit to do it
automatically every time I remove power. How about like a 555 chip or some
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.

Bill