A Beginner's Guide to Circuits

9THE LED MARQUEE

THIS CIRCUIT CREATES A RUNNING LIGHT, LIKE AN OLD THEATER MARQUEE.

THE CIRCUIT DIAGRAM

THE PARTS LIST

PART	VALUE	DESCRIPTION
R1, R2	10 kΩ	Two standard resistors
R3	470 Ω	Standard resistor
C1	4.7 μF	Polarized capacitor
L1 to L10	LED	Standard light-emitting diodes
U1	NE555	555 timer IC
U2	CD4017B	4017 decade counter IC

ABOUT THE CIRCUIT

This circuit uses a 555 timer and a 4017 decade counter, both integrated circuits. The voltage of the 555 timer’s pin 3 switches between high and low repeatedly, as you saw in ...