CD4017 Example Circuit – Running LEDs

An extensively favored endeavor for hobbyists employing this chip involves crafting a dynamic LED display circuit. The operation proceeds as follows

An extensively favored endeavor for hobbyists employing this chip involves crafting a dynamic LED display circuit. The operation proceeds as follows:

An astable configuration is established for the 555 Timer, endowing it with oscillator capabilities that yield a clock signal. This clock signal is directed to the clock input of IC 4017. Whenever the clock input registers a high level, the counter within the 4017 advances, causing the subsequent output to assume a high state. LEDs are linked to these outputs, simulating a dynamic motion akin to a procession along a path. Check the component list here.

The pace at which the 555 Timer's output attains a HIGH state within a second defines the frequency, denoted in Hertz (Hz). For instance, a frequency of 10 Hz signifies a recurrence of ten instances in one second. Consequently, the LED undergoes ten displacements within that timeframe.

The determination of frequency relies upon the interplay between resistors R1 and R2, along with capacitor C1, following this prescribed formula:

Frequency = 1.44 / ((R1 + R2 + R2) * C1)

It's crucial to ensure R1's value remains at or above 1 kΩ to prevent any potential damage to the chip, particularly when Pin 7 (Discharge) is linked to ground.

For those interested in exploring various values, the 555 Timer calculator stands ready to assist in this experimentation.