This article explain how to blink or flash an LED with the 555 timer IC. It's simple project for beginners to go with.
It's expected that u should have had the basic knowledge of the 555 timer pins, their functions and how they are connected to circuits, as well as understanding it modes ( astable and mono stable vibration modes) before you can start making projects with it. If you are a beginner you can quickly learn about the 555 timer here.
Let's quickly recap 555 timer pinout before we move.
Pin 1-Ground: It is connected to ground as usual. For the timer to function this pin should be connected to ground.
Pin 2-TRIGGER: The negative input comparator No 1. A negative pulse on this pin “sets” the internal Flip-flopwhen the voltage drops below 1/3Vcc causing the output to switch from a “LOW” to a “HIGH” state
Pin 3-OUTPUT: This pin also has no special function. This pin is drawn from PUSH-PULL configuration formed by transistors.This pin gives the output.
Pin 4-Reset: There is a flip-flop in the 555 IC timer chip. The output of flip-flop controls the chip output at pin 3 directly. This pin is connected to Vcc for the flip-flop to stop from hard resetting.
Pin 5-Control Pin: The control pin is connected from the negative input pin of comparator one. The function of this pin to give the user the direct control over the first comparator.
Pin 6-THRESHOLD: Threshold pin voltage determines when to reset the flip-flop in the timer. The threshold pin is drawn from positive input of comparator1.
Pin 7-DISCHARGE: 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”.
Pin 8-Power or VCC: This pin also has no special function. It is connected to a positive voltage.
Electronics Components needed.
- 9v battery
- 2 LEDs
- Capacitor
- NEC555 timer
- Resistors
- Connecting wire
- Bread board
- 9v battery connector.
The 555 timer IC operates in modes Astable mode Monostable mode Bistable mode Astable mode Astable mode means there will be no stable levels at the output. Thus the output will fluctuate from high and low. This character of the astable output is used as a clock or square wave output for many applications
Tags:
DIY