LCD-LED Display

Simple LED Blinking Circuits

A semiconductor light emitting diode is known as an LED Blinking (Light Emitting Diode). We know that a diode permits current to flow in one way but not the other, causing damage to the circuit’s components. LEDs do the same job, except they emit a little light when the current is allowed, indicating to the average person that the circuit is operational. LEDs can be used in a variety of ways. They are mostly used for visual indication in electrical equipment, measuring and engaging with processes, presenting images on television or in advertising hoardings, and so on.

Two LED blinking circuits are given below. First one is dancing bi-color LEDs (two different color LEDs) where the two color LED will run in sequence. In the second circuit, we will blink the LEDs in regular period of time.

Outline

  • Dancing Bi – Color LED Circuit:
    • Block Diagram of Bi-Color LED Circuit:
    • Bi-Color LED Dancing Lights Circuit Diagram:
  • LED Flasher Circuit:
    • Block Diagram of LED Flasher Circuit:
    • LED Flasher Circuit Diagram:
    • LED Blinking Circuits Applications:

Dancing Bi – Color LED Circuit:

Generally we use small voltage bulbs in the dancing bulbs. This circuit is mainly used in the occasions, decoration articles or in visual indication sign boards etc. In this project, we use bi-color LEDs for sequential running light.

Block Diagram of Bi-Color LED Circuit:

Block Diagram of Dancing Bi-color LEDs


Timer is used for setting the sequential flow rate for the bi-color LED panel. The CD4017 is a decade counter which provides the timing and will make the LED ON/OFF according to the time determined.

Main Components in this Circuit:

CD4017: The CD4017 is a 16-pin decade counter with just 10 output pins. The clock pulses will cause the 4017 to be triggered. The decade counter’s main function is as follows: When a clock pulse is used as an input, only one output pin is set to high for the first clock pulse, and the others are set to low. Another output pin is made high for the second clock pulse, and the other pins are made low, and so on. According to the pulse width, the output pin’s time period is long. CD4017 is utilised in a variety of applications that require a counter.

Bi-Color LED Dancing Lights Circuit Diagram:

CD4017 clock pulses from output pins timing diagram is shown below:

CD4017 Clock pulses from output pins timing diagram

Bi-Color LED Dancing Lights Circuit Diagram:

LED Blinking

Circuit Diagram Explanation:

  • The counter should be connected to the Bi-color LED as illustrated in the schematic. The anode of the first bicolor LED is connected to the anode of the second bicolor LED of the tenth bicolor LED, and the remaining LEDs are connected in the same way, with the exception that the second anode of the first bicolor LED is connected to the CD4017’s reset pin. The cathode of all bicolor LEDs is grounded.
  • The 555 timer in astable multivibrator mode and the decade counter CD4017 are responsible for the circuit’s principal operation; the 555 timer generates a low frequency clock pulse and feeds it to the decade counter, which controls the LEDs’ sequential operation.
  • The resistance of a variable resistor can be changed, changing the pulse width. The time duration for running the LEDs will change if the pulse width is modified. The LEDs can be turned on and off quickly or slowly. The variable resistor can change the running speed. For continuous lighting, the first anode of the 10th bicolor LED is connected to the reset pin of the decoding counter.

LED Flasher Circuit:

LED Flasher is a simple circuit which will blink the LEDs in regular time period. This circuit can be used for decoration purpose or can be used for a signaling purpose and many more.

Block Diagram of LED Flasher Circuit:

LED Flasher Block Diagram

The 555 timer is used to generate the PWM signal which will cause the LEDs to blink. The speed of the blinking by LED is determined by the potentiometer connected to the 555 timer. The PNP transistor is used to flash or blinks the LEDs.

LED Flasher Circuit Diagram:

LED Flasher Circuit Diagram

Circuit Explanation:

  • The 555 timer is made to be configured as a astable multivibrator. The potentiometer which is connected to the timer should be preset and also to adjust the blinking or flashing speed of the LEDs.
  • In this circuit, bicolor LEDs are utilised and are linked as indicated in the design. The output of the 555 timer is passed to the transistor, which functions as an inverter, resulting in the PWM signal. Transistors and LEDs will turn on when the pulse generated by 555 timers is low. When the transistor’s input is high, the transistor is turned off, and the LEDs are turned off. Every pulse width signal cycle, the LEDs will turn on and off. The LEDs will flash as a result of this technique.

LED Blinking Circuits Applications:

  • Dancing LED circuit can be used for any visual sign indication in any highways or it can be used in advertisement hoarding also.
  • LED blinking circuit can be used in signaling purpose (It can be used as signal for help, if you are in danger)
  • LED blinking circuit can be used as flashing beacon.
  • LED blinking circuit can be used as vehicle indicator when it is broke down in the middle of the road. It can be used in operation theaters or offices as an indication that you are engaged in work.
  • There are lots of applications with these two circuits.


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