Automatic light flasher unit

 Automatic light flasher unit

Introduction

Many times a simple low-cost automatic flasher light may be required for many of our project combinations. Though it can be built with various circuit designs, this automatic flasher is unique in the sense of very low cost and very much simple to build. As a fact, many electronics enthusiasts and hobbyists love to build this circuit design for their electronics projects. Students readily select this design for their project work as it is not complicated besides being cheap and sure about its performance to gain high rewards in their curriculum activities. The simplicity of the circuit lies with just two silicon-based transistors and can be assembled on any general-purpose PCB quickly and easily. The versatility of the circuit is unique in that it can be used in various ways which are described in our next topic. 

Utility of the circuit design

This automatic flasher circuit is used in various ways. It can be put into multipurpose and multi-use with one's own ingenuity to serve for the most. 

1. Just a mini flasher light for attention or for attraction

2. The LDR (Light Dependent Resistor) serves many uses as noninterruption counter, interruption counter, detecter, light-activated as well as darkness activated sensor, etc. As such it gives one 101 ideas to make use of it. 

3. Thus the flasher is put into use according to one's own requirement of function to achieve the result. Alarm circuits are being designed simply with this circuit.

This shows that the circuit is very famous among electronics enthusiasts.

The circuit design

The full circuit schematic is presented here and it is clear that the schematic appears to be very simple and straightforward. Even a novice can understand the various connections involving very few components and uses just two transistors. 

The LDR is very wisely used in the circuit for the achievement of required functionalities.

 

As a flasher 6v bulb is used here which can be easily replaced with LED, Relay or Calculator for various outputs. 

 

The circuit uses a 6V power supply and the current consumption will depend upon what output stage is connected as a load to the Q2 transistor.

The working of the circuit

Q1 and Q2 transistors are connected in such a way that the circuit oscillates and the light flashes according to the speed of the oscillation which is determined by the electrolytic capacitors and LDR. Whenever light falls on the LDR, it activates the circuit for oscillation and the light flashes.  R3 preset determines the sensitivity of the LDR. Thus LDR acts as low as well as high resistance depending upon the light intensity that falls over it.

 

Parts List

Q1 = BC547B Transistor

Q2=BC517 Transistor

R1 =2.2K ohm resistor

R2=1K ohm resistor

R3=250 ohm preset

R4=3.3K ohm resistor

C1,C2= 220 MFD/16V electrolytic capacitors

LDR= Light Dependent Resistor

L= 6v, 50mA lamp

VCC=6V DC power supply 

 

Assembling points

The circuit can be assembled on any general-purpose printed board. However, for ease of assembling and for a professional appearance, a ready-made PCB design is given here which ensures neat and compact assembling of the circuit 

 

PCB Assembling

PCB design of the circuit is given here. It has been taken more care in designing for the easy of novice to assemble it on this readymade board. 

 

 

 

 

 

 

The component layout of the board

One can easily locate the components of the circuit design on the PCB which helps in identifying them and their location. 

 

 

 

 

 

 

Copper Track of the PCB

The design can be easily etched on a copper clad board and the PCB can get ready for the assembling work.

 

 

 

 

Summing up

Any electronics enthusiast can relish the versatility of the circuit and would not miss including it in one's own project. Please share your suggestions and comments on this topic for better improvement of the same.