C-MOS line selector
Electronic
74HC00

It isn't too hard to think of situations where we might want to send input data to two or more different outputs. This project shows how we can use a network of NAND gates to help us do just that.

You can see that we use a multivibrator and three NAND gates in this circuit, You can leave the select switch at either up or down position when building this project. You'll see that LED 1 is blinking. But what are LED 2 and LED 3 doing?

If the select switch is at the down position, LED 2 is blinking; if it is up, LED 3 blinks.

As you can see on the schematic, setting the select switch up or down controls the inputs to the two NANDs that light LED 2 or LED 3. With the select switch at the down position, the NAND controlling LED 2 gets one steady input of 1.

The output of the multivibrator supplies the other input. As the multivibrator's output switches from 0 to 1, the NAND controlling LED 2 also switches its output from 0 to 1.

The opposite happens when you set the select switch up. Now the NAND controlling LED 3 gets a steady input of 1 so that LED 3 can go on and off according to the input from the multivibrator.