The post explains how to build an 18 LED chaser circuit through a simple cascading of two 4017 ICs, and some passive electronic components.
What is a Light Chaser
Decorative lights arranged in different moving patterns look very interesting and are surely eye catching and that’s why these types of lighting arrangement have gained immense popularity in today’s world.
Though the more complex lighting might need the incorporation of microcontroller ICs, simpler yet very interesting light effects can be generated through ordinary ICs, which require very few components for the configuration.
A light chaser circuit is a configuration which generates a running or chasing light pattern which goes on repeating itself from start to finish, producing a very eye catching and fascinating light pattern. The lights connected are mostly LEDs, however it can be modified for using with mains operated lamps also.
Here we are discussing how to make a simple LED running light which can be built by any newcomer in the field albeit the individual has some knowledge of soldering and regarding the commonly used electronic components.
The concept of a light chaser discussed here utilizes the popular Johnson’s decade counter IC 4017 for getting the desired light chasing effect. IC 4049 is used as the Oscillator
Another IC 4049 provides the clock signals to the counter ICs. We all have probably seen how the IC 4017 can be configured for creating the light chasing effect using LEDs, however the number of maximum LEDs supported by this IC is not more than ten. In this article we’ll learn how to make an eighteen LED light
chaser by cascading two of these ICs.
Cascading two IC 4017 Johnsons Counter for the 18 LED Effect
Looking at the above light chaser circuit diagram we see how the two ICs are configured so that the “chasing” or "running"of the LEDs at its outputs are carried on for 18 LEDs. The diodes included in the circuit especially are responsible for switching the ICs into a cascading action.
The diodes make sure the IC outputs are carried forward from one IC to another, so that the “chasing” effect is pulled for the entire 18 LEDs in the array.
The whole circuit can be built over a general purpose PCB, and connected together by soldering with the help of the shown diagram.
The circuit can be operated in between 6 volts to 12 volts.
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R1, R3, R4 = 2k7,
R5 = 100k,
C1 = 10 uF/25V,
N1, N2, N3, N4, N5, N6 = IC 4049,
IC1,2 = 4017,
All diodes are = 1N4148,
PCB = General purpose
LED = as per choice.
The above 18 LED cascaded chaser circuit can be also conveniently built using a 555 astable circuit, as shown below:
Video Clip of the above circuit in operational mode:
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