Great explanation! Thank you for providing an architectural synopsis of
what's involved.
Peter

"Harold Ryan" wrote in message
...
Hi Chris:

The circuit that you want to build consists of three sections. (1) The
momentary switch must be connected to a debounce circuit. This will create
only one edge when the switch is closed or opened. This is accomplished by
using a resistor and a cap to create a lowpass filter and a buffer logic
device like a 'AND' gate. The secret is to use an additional feed back
resistor that creates hysteresis.

The second section is the flip-flop that is wired to toggle. U can use a
74HC74 D type flip-flop or even a JK flip flop. The 3rd section is the
decode logic. If you want to just toggle an LED then there is no decode
logic. Just connect the output of the flip-flop to an LED or thru an
additional buffer chip. If you want to have 3 LEDS to sequence, just add
another flip-flop and use a couple NAND gates to decode the two outputs of
the two flip flops to generate 3 outputs. Use 74HCXXXX chips because the
crossover threshold voltage is 5volts/2 or 2.5 volts.

Harold