The article is being published in collaboration with JLCPCB. They supply high quality PCBs at a very reasonable price. They also can provide SMT circuit assembly.

We thanks to our sponsor JLCPCB for sponsoring us PCBs for this project circuit.

Thanks To JLCPCB.

$2 for 1-4 Layer PCBs.

Get SMT Coupons -

In this circuit, we are going to teach you making a simple electronics project using NE-555 timer IC. An LED flasher circuit is a circuit which flashes the LED- meaning turns it ON-OFF, ON-OFF, ON-OFF. The 555 timer chip is a very versatile IC, because when connected correctly, it can it can create pulses of current at specific time intervals decided by the resistor-capacitor (RC) network.

The circuit can be used as a flashing metronome, dark room timer, memo-reminder or other similar applications. The IC is connected as a stable multi vibrator with a duty cycle of about 10%.

In figure 1 the LED will be ON for a short period of time and OFF for a longer period. The duty cycle can be reversed if the LED is connected as shown in figure 2 but the battery consumption will also increase due to the fact that the LED will stay ON for a longer period of time.

Component List -

To make this LED flasher circuit using NE-555 timer IC, we might need some electronics component. You can order your assembled SMT circuit form JLCPCB.

All components list have been given below –

Component List –

  1. Time IC – NE 555
  2. Resistor –68 KΩ * 2
  3. Capacitor – 100uF/25v *2
  4. LED – 3v (20mA)
  5. Power Source – 9v

NE555 Pin Out -

NE555 timer IC is an integrated circuit used in a variety of timer, delay, pulse generation and oscillator applications. Derivatives provide two or four timing circuits in one package. There are totally 8 legs of a timer IC.

As well as the 555 timer, there is also available the NE556 timer oscillator.

The internal block diagram and schematic of the 555 timer are highlighted with the same color across all three drawings to clarify, how the chip is implemented.

  1. GND - The ground pin connects the 555 timer to the negative (0v) supply rail.
  2. TRIG - The negative input to comparator No 1. A negative pulse on this pin “sets” the internal Flip-flop when the voltage drops below 1/3Vcc causing the output to switch from a “LOW” to a “HIGH” state.
  3. OUT - The output pin can drive any TTL circuit and is capable of sourcing or sinking up to 200mA of current at an output voltage equal to approximately Vcc – 1.5V so small speakers, LEDs or motors can be connected directly to the output.
  4. RESET - This pin is used to “reset” the internal Flip-flop controlling the state of the output, pin 3. This is an active-low input and is generally connected to a logic “1” level when not used to prevent any unwanted resetting of the output.
  5. CONT - This pin controls the timing of the 555 by overriding the 2/3Vcc level of the voltage divider network. By applying a voltage to this pin the width of the output signal can be varied independently of the RC timing network. When not used it is connected to ground via a 10nF capacitor to eliminate any noise.
  6. THRES - The positive input to comparator No 2. This pin is used to reset the Flip-flop when the voltage applied to it exceeds 2/3Vcc causing the output to switch from “HIGH” to “LOW” state. This pin connects directly to the RC timing circuit.
  7. DISCH - The discharge pin is connected directly to the Collector of an internal NPN transistor which is used to “discharge” the timing capacitor to ground when the output at pin 3 switches “LOW”.
  8. VCC - This is the power supply pin and for general purpose TTL 555 timers is between 4.5V and 15V.

Feature -

  • Variety of Timer
  • Delay Timer
  • Pulse generation
  • Oscillator Applications
  • Lamp and LED flashers
  • Logic clocks
  • Tone generations
  • Security alarms
  • Position Modulation
  • LED blinker

Circuit Connection – Step...

Read more »