Simple LED Running Light Circuit (Flashing LEDs)
In this project, we have designed a simple Flashing LED Circuit. We have used two sets of LEDs (3 on one side and 3 on the other) that will be turned on alternatively so that the outcome is a bright flashing LEDs.
Components Required
2 x 2N2222A (NPN Transistor)
2 x 22µF – 50V Capacitor (Polarised)
2 x 46 KΩ Resistor (1/4 Watt)
6 x 8mm Bright White LED
12V Power Supply
Connecting Wires
Breadboard
Working of the Project
From the circuit diagram, it is clear that the project is based on simple Astable or a Free Running Multivibrator. When switch on the circuit, one transistor will be ON (in Saturation) and the other will be OFF (Cutoff).
Assuming Q1 is ON and Q2 is OFF, the Capacitor C2 will charge through series LEDs. Since the LEDs are connected in the path of the current, they will light up.
During this time, the transistor Q2 is OFF because of the discharging capacitor C1 (as the negative plate is connected to the base of Q2). After the time constant C1R1, the capacitor C1 is completely discharged and starts charging through R1.
The charging direction is reverse. As the capacitor charges, it builds up sufficient voltage (0.7V) to turn ON the transistor Q2. At this time, the capacitor C2 starts discharging through Q2.
As the plate of the capacitor C2, which is connected to the base of the transistor Q1, becomes negative, the transistor Q1 is turned OFF and this set of LEDs are turned OFF.
Now, the capacitor C1 starts to charge from the corresponding series LEDs (through base of Q2). As this set of LEDs are connected in the current path, they will be turned ON.
Now the capacitor C2 discharges and after complete discharge, it will start charging through R2. As the charge builds up in the capacitor C2, when the voltage reaches 0.7V, it will turn ON the transistor Q1. From this point the process repeats as earlier.
LED Chaser Circuit using CD4017 and 555
The second project in the LED Knight Rider Series is an LED Chaser circuit using CD4017 Decade Counter and 555 Timer IC. We will see the circuit diagram, components used and the working of this project
Circuit Diagram
Components Required
1 x CD4017 Decade Counter IC
1 x 555 Timer IC
1 x 18 KΩ Resistor (1/4 Watt)
1 x 2.2 KΩ Resistor (1/4 Watt)
1 x 100 KΩ Potentiometer
1 x 1 µF – 50V Capacitor (Polarised)
1 x 0.1 nF Ceramic Disc Capacitor (100 pF code 101)
10 x 8mm Bright White LEDs
Connecting Wires
5V Power Supply
Breadboard
Working of the Project
In this project, we have designed a simple LED Chaser Circuit, where the LEDs turn ON one after the other and give us the effect of one LED chasing the other. We will now see the working of this project.
First thing we notice in the circuit diagram is that there are two parts in the circuit: the 555 Timer part and the CD4017 Decade Counter IC part with LEDs. The 555 Timer IC in this project is configured as an Astable Multivibrator.
In this mode, it generates a pulse whose frequency is determined by the components R1 (2.2 KΩ), R2 (18 KΩ), VR1 (100 KΩ) and C1 (1µF). The frequency of the pulse can be controlled by adjusting the 100 KΩ POT.
This pulse is given to the CD4017 Decade Counter IC as its clock input. By understanding the working of CD4017, for every clock pulse it receives at the Clock Input pin, the count in increased by 1 and as a result each output pin will be HIGH for every corresponding clock pulse.
As it is a decade counter, we will get a count of 10 and since we connected the bright white LEDs to the output pins, each LED will be turned ON when the corresponding pin becomes HIGH.
After 10 clock pulses, the count is reset and will start from the beginning. If the LEDs were placed in a circular fashion, we get the feel and look a Chasing LED effect.
Two Way Running LEDs with 11 LEDs, CD4017 and 555 Timer IC
This is another running LED circuit but the difference between this and the previous Running LEDs circuit and this circuit is that in the previous circuit, it was designed as a one way running LEDs circuit whereas in this circuit, the LEDs will be running in two ways.
Circuit Diagram
Components Required
1 x CD4017 Decade Counter IC
1 x 555 Timer IC
1 x 18 KΩ Resistor (1/4 Watt)
1 x 2.2 KΩ Resistor (1/4 Watt)
1 x 470 Ω Resistor (1/4 Watt)
1 x 100 KΩ Potentiometer
1 x 1 µF – 50V Capacitor (Polarised)
1 x 0.1 nF Ceramic Disc Capacitor (100 pF code 101)
8 x 1N4007 PN Junction Diodes
11 x 8mm Bright White LEDs
Connecting Wires
12V Power Supply
Breadboard
Working of the Project
The working of the Two Way Running LEDs project is similar to that of the LED Chaser Circuit except that the orientation of the LEDs is different. We will see the working of this project now.
The 555 Timer part (the operation is similar to the one explained in the above circuit) generates a pulse signal, which is given to the CD4017 Counter as the clock input. The LED6, which is connected to the Q0 of the CD4017 will light up first.
The LED5 and LED7, which are connected to Q1 of CD4017, will light up next. The connections continue as shown in the circuit diagram and this process continues till Q5, which is connected to LED1 and LED11. Until this step, one way lighting of the LED will be completed.
In order to achieve the two way lighting up of the LED, Q6 is connected to LED2 and LED10, Q7 is connected to LED3 and LED9 and so on.
The final effect will be a Two Way Running LEDs and the sequence will be as follows: LED6 (Q0), LED5 – LED7 (Q1), LED4 – LED8 (Q2), LED3 – LED9 (Q3), LED2 – LED10 (Q4), LED1 – LED11(Q5) for one way and followed by LED2 – LED10 (Q6), LED3 – LED9 (Q7), LED4 – LED8 (Q8), LED5 – LED7 (Q9).
LED Running Lights – LED Knight Rider Circuit Diagram
Components Required for the Circuit:
IC
NE555 – 1
CD4017 – 2
Resistor
R1 (1K) – 1
R2 (100K) – 1
R3 (10K) – 1
VR1 (100K) – 1
C2, C1 (.1uf) – 2
D1-D9 (1N4148) – 9
Transistor (BC547) – 1
LED1-LED9 – 9
In this project, we have designed a simple Flashing LED Circuit. We have used two sets of LEDs (3 on one side and 3 on the other) that will be turned on alternatively so that the outcome is a bright flashing LEDs.
Components Required
2 x 2N2222A (NPN Transistor)
2 x 22µF – 50V Capacitor (Polarised)
2 x 46 KΩ Resistor (1/4 Watt)
6 x 8mm Bright White LED
12V Power Supply
Connecting Wires
Breadboard
Working of the Project
From the circuit diagram, it is clear that the project is based on simple Astable or a Free Running Multivibrator. When switch on the circuit, one transistor will be ON (in Saturation) and the other will be OFF (Cutoff).
Assuming Q1 is ON and Q2 is OFF, the Capacitor C2 will charge through series LEDs. Since the LEDs are connected in the path of the current, they will light up.
During this time, the transistor Q2 is OFF because of the discharging capacitor C1 (as the negative plate is connected to the base of Q2). After the time constant C1R1, the capacitor C1 is completely discharged and starts charging through R1.
The charging direction is reverse. As the capacitor charges, it builds up sufficient voltage (0.7V) to turn ON the transistor Q2. At this time, the capacitor C2 starts discharging through Q2.
As the plate of the capacitor C2, which is connected to the base of the transistor Q1, becomes negative, the transistor Q1 is turned OFF and this set of LEDs are turned OFF.
Now, the capacitor C1 starts to charge from the corresponding series LEDs (through base of Q2). As this set of LEDs are connected in the current path, they will be turned ON.
Now the capacitor C2 discharges and after complete discharge, it will start charging through R2. As the charge builds up in the capacitor C2, when the voltage reaches 0.7V, it will turn ON the transistor Q1. From this point the process repeats as earlier.
LED Chaser Circuit using CD4017 and 555
The second project in the LED Knight Rider Series is an LED Chaser circuit using CD4017 Decade Counter and 555 Timer IC. We will see the circuit diagram, components used and the working of this project
Circuit Diagram
Components Required
1 x CD4017 Decade Counter IC
1 x 555 Timer IC
1 x 18 KΩ Resistor (1/4 Watt)
1 x 2.2 KΩ Resistor (1/4 Watt)
1 x 100 KΩ Potentiometer
1 x 1 µF – 50V Capacitor (Polarised)
1 x 0.1 nF Ceramic Disc Capacitor (100 pF code 101)
10 x 8mm Bright White LEDs
Connecting Wires
5V Power Supply
Breadboard
Working of the Project
In this project, we have designed a simple LED Chaser Circuit, where the LEDs turn ON one after the other and give us the effect of one LED chasing the other. We will now see the working of this project.
First thing we notice in the circuit diagram is that there are two parts in the circuit: the 555 Timer part and the CD4017 Decade Counter IC part with LEDs. The 555 Timer IC in this project is configured as an Astable Multivibrator.
In this mode, it generates a pulse whose frequency is determined by the components R1 (2.2 KΩ), R2 (18 KΩ), VR1 (100 KΩ) and C1 (1µF). The frequency of the pulse can be controlled by adjusting the 100 KΩ POT.
This pulse is given to the CD4017 Decade Counter IC as its clock input. By understanding the working of CD4017, for every clock pulse it receives at the Clock Input pin, the count in increased by 1 and as a result each output pin will be HIGH for every corresponding clock pulse.
As it is a decade counter, we will get a count of 10 and since we connected the bright white LEDs to the output pins, each LED will be turned ON when the corresponding pin becomes HIGH.
After 10 clock pulses, the count is reset and will start from the beginning. If the LEDs were placed in a circular fashion, we get the feel and look a Chasing LED effect.
Two Way Running LEDs with 11 LEDs, CD4017 and 555 Timer IC
This is another running LED circuit but the difference between this and the previous Running LEDs circuit and this circuit is that in the previous circuit, it was designed as a one way running LEDs circuit whereas in this circuit, the LEDs will be running in two ways.
Circuit Diagram
1 x CD4017 Decade Counter IC
1 x 555 Timer IC
1 x 18 KΩ Resistor (1/4 Watt)
1 x 2.2 KΩ Resistor (1/4 Watt)
1 x 470 Ω Resistor (1/4 Watt)
1 x 100 KΩ Potentiometer
1 x 1 µF – 50V Capacitor (Polarised)
1 x 0.1 nF Ceramic Disc Capacitor (100 pF code 101)
8 x 1N4007 PN Junction Diodes
11 x 8mm Bright White LEDs
Connecting Wires
12V Power Supply
Breadboard
The working of the Two Way Running LEDs project is similar to that of the LED Chaser Circuit except that the orientation of the LEDs is different. We will see the working of this project now.
The 555 Timer part (the operation is similar to the one explained in the above circuit) generates a pulse signal, which is given to the CD4017 Counter as the clock input. The LED6, which is connected to the Q0 of the CD4017 will light up first.
The LED5 and LED7, which are connected to Q1 of CD4017, will light up next. The connections continue as shown in the circuit diagram and this process continues till Q5, which is connected to LED1 and LED11. Until this step, one way lighting of the LED will be completed.
In order to achieve the two way lighting up of the LED, Q6 is connected to LED2 and LED10, Q7 is connected to LED3 and LED9 and so on.
The final effect will be a Two Way Running LEDs and the sequence will be as follows: LED6 (Q0), LED5 – LED7 (Q1), LED4 – LED8 (Q2), LED3 – LED9 (Q3), LED2 – LED10 (Q4), LED1 – LED11(Q5) for one way and followed by LED2 – LED10 (Q6), LED3 – LED9 (Q7), LED4 – LED8 (Q8), LED5 – LED7 (Q9).
Circuit Diagram of LED Knight Rider Circuit Diagram:
Components Required for the Circuit:
IC
NE555 – 1
CD4017 – 2
Resistor
R1 (1K) – 1
R2 (100K) – 1
R3 (10K) – 1
VR1 (100K) – 1
C2, C1 (.1uf) – 2
D1-D9 (1N4148) – 9
Transistor (BC547) – 1
LED1-LED9 – 9
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