What is a LED chaser?
LED chaser is one type of LED blinking circuit, where a certain number of LEDs are continuously turned on and off in a serialized manner. The working of the LEDs in the circuit is quite similar to a chaser circuit. That is why, the circuit is known as LED chaser. You can use any number of LEDs in the circuit according to your need. But the working principal will remain same in all the cases.
Where are LED chaser used?
LED chaser are mainly used in decoration purpose during festivals. LED chaser can be used in home decoration as well as in the office decoration or in some other areas. LED chaser make everything very colourful and attractive. Due to this reason, it is also used in advertising purpose (in big screen Led display).
How do you make a LED chaser with CD 4017 IC?
In a LED chaser, LEDs are glowing in a sequential manner (from one end to other end). To achieve this sequential or serialized manner, you have to use a counter IC along with a clock pulse generator IC. In this LED chaser circuit, I used the CD 4017 IC (A decade counter) and the NE 555 timer IC (Clock pulse generator IC). Here I will describe the full process of making this LED chaser circuit including the pros and cons.
LED chaser circuit using 4017 and 555 –
At first take 10 pieces of red LED. Then identify the positive and negative terminal of the LED (The bigger pin is positive and the smaller pin is negative). Now take a veroboard for connecting the circuit components. Take the 10 LED and put it in the veroboard. Then connect all the negative pins of the LED together. Also use a 1 Kilo Ohm resistor to limit the current in the LEDs. Then connect the resistor with the ground supply. Now we need some other circuit components to complete the remaining circuit. The circuit components are – NE 555 Timer IC, CD 4017 IC, Potentiometer, 10uF Capacitor and 1 Kilo ohm Resistor. Now put this components in the veroboard and do the connections as mentioned below.
Connection between LED and CD4017 IC –
(1) Positive pin of LED 1 with pin 3 of CD 4017 IC
(2) Positive pin of LED 2 with pin 2 of CD 4017 IC
(3) Positive pin of LED 3 with pin 4 of CD 4017 IC
(4) Positive pin of LED 4 with pin 7 of CD 4017 IC
(5) Positive pin of LED 5 with pin 10 of CD 4017 IC
(6) Positive pin of LED 6 with pin 1 of CD 4017 IC
(7) Positive pin of LED 7 with pin 5 of CD 4017 IC
(8) Positive pin of LED 8 with pin 6 of CD 4017 IC
(9) Positive pin of LED 9 with pin 9 of CD 4017 IC
(10) Positive pin of LED 10 with pin 11 of CD 4017 IC
After connecting the LED in the circuit, you have to do the supply connection in the CD 4017 IC. Follow the listed steps for further connection –
(1) Connect the pin 16 (VCC pin) of CD 4017 IC with the positive terminal of battery.
(2) Connect the pin 8 (Ground pin) of CD 4017 IC with the negative terminal of battery.
You have to strictly follow this order of connections for making the LED chaser. If you change the connections, it will not work properly. After doing the above mentioned connections, you have to connect the NE 555 Timer IC in the circuit.
Connection between NE 555 and CD 4017 IC –
(1) Connect the pin 3 (Output pin) of NE 555 IC with the pin 14 (Clock pin) of CD 4017 IC
(2) Connect the pin 4 (Reset pin) and pin 8 (VCC pin) of NE 555 timer IC with the positive terminal of battery.
(3) Connect the pin 1 (Ground pin) of NE 555 timer IC with the negative terminal of battery.
Now you have to connect the other circuit components (Like capacitor, potentiometer and resistor) in the veroboard. The connections are shown here –
(1) Connect the potentiometer in between pin 2 and pin 7 of NE 555 timer IC.
(2) Connect the positive terminal of capacitor with the pin 2 of NE 555 timer IC. Then connect the negative terminal of capacitor with the pin 1 of NE 555 timer IC.
(3) Connect the 1 Kilo ohm resistor in between pin 7 and pin 8 of NE 555 timer IC.
The circuit connection of LED chaser is almost complete. You have to follow the above mention steps for designing the circuit. For better understanding take a look in the circuit diagram, given below –
Testing of LED Chaser Circuit –
Now you have to provide the power supply in the circuit. For this purpose, I used a 9 volt battery. Once you connected the battery in the circuit, all LEDs will start glowing in a serialized manner (From start to end). This serialized manner of the LED blinking is known as LED chaser. You can also adjust the speed of LED chaser by trimming the value of potentiometer. If the potentiometer is set to a high value, the speed of LED chaser will be high. And if the potentiometer is set to a low value, the speed of LED chaser will be slow.
Beside this, the speed of the LED chaser varies with the value of the capacitor. In this LED chaser circuit I used 10 uF capacitor. If you increase the value of capacitor (for example 100 uF), the speed of the LED chaser will decrease. This is how you can adjust and use the LED chaser in many projects for different application.
