I remember doing a circuit like that in Basic Digital Elec. It's called a JK Flip-Flop with J and K tied to positive. You'd need 4 nand gates if I remember,
2x3 input nand gates and 2 2 input nand gates.
search for J-K Flip-Flop. Both J and K inputs should be tied to positive, and the CLK to your switch.
I believe this could also be done using simple transistors, but I don't remember that far back.
Why would you want this though? an push button On-Off switch is much-much easier (and cheaper).
This variation of the JK Flip-Flop is called a T Flip-Flop (for Toggle).
I found a sample structure:http://hyperphysics.phy-astr.gsu.edu/hbase...lipflop.html#c1
The structure is :http://hyperphysics.phy-astr.gsu.edu/hbase...lipflop.html#c2
disregard the term "Clock edge" since that will just be the signal from the momentary switch going from GND to Positive then back to GND This post has been edited by nyarrgh: Nov 7 2003, 11:08 PM