Clock signal generator using 7400 IC (PCB)

This clock signal generator is an astable circuit which uses the TTL 7400 integrated circuit. The 7400 IC has four 2 inputs NAND gates (NOT AND) but we only use two gates. Suggested Printed Circuit Board (PCB)

Astable multivibrator using NAND gates

This astable multivibrator uses two NAND gates of the 4 available on the 7400 TTL integrated circuit. Two LEDs are used to view the status or logic output of each gate.

LED Sequencer using 4017.

This circuit has 10 LEDs connected to the 4017 decade counter outputs. The LEDs light up in sequence. (only one is ON at a time)