P-1644--Automatic Street Light Controller 3
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Transcript of P-1644--Automatic Street Light Controller 3
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1. Introduction
Automatic Street Light Control System is a
simple and powerful concept, which uses transistor as a
switch to switch ON and OFF the street light
automatically. By using this system manual works are
remoed. !t automatically switches ON lights when the
sunlight goes "elow the isi"le region of our eyes. !t
automatically switches OFF lights under illumination "y
sunlight. #his is done "y a sensor called Light
$ependant %esistor &L$%' which senses the light
actually like our eyes.
By using this system energy consumption
is also reduced "ecause now(a(days the manually
operated street lights are not switched o) properly
een the sunlight comes and also not switched on
earlier "efore sunset. !n sunny and rainy days, ON time
and OFF time di)er signi*cantly which is one of thema+or disadantage of using timer circuits or manual
operation.
#his pro+ect eploits the working of a
transistor in saturation region and cut(o) region to
switch ON and switch OFF the lights at appropriate time
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with the help of an electromagnetically operated
switch.
Automatic Streetlight needs no manual
operation of switching ON and OFF. #he system itself
detects whether there is need for light or not. hen
darkness rises to a certain alue then automatically
streetlight is switched ON and when there is other
source of light, the street light gets OFF. #he etent of
darkness at which the street light to "e switched on can
also "e tailored using the potentiometer proided in the
circuit.
2. Principle
#he automatic streetlight control system operates on
-/ 0 $C supply. #he automatic streetlight controller has
a photoconductie deice whose resistance changes
proportional to the etent of illumination, which
switches ON or OFF the L1$ with the use of transistor
as a switch
.
Light dependent resistor, a
photoconductie deice has "een used as the
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transducer to conert light energy into electrical
energy. #he central dogma of the circuit is that the
change in oltage drop across the light dependent
resistor on illumination or darkness switches the
transistor "etween cut(o) region or saturation region
and switches OFF or ON the L1$.
3. Block Diagram Circuit Diagram
3.1 Block Diagram
3.1.1 Individual Block Explanation
Power supply AC power supply is stepped down,recti*ed and *ltered to get almost ripple(free $C outputfor the operation of the circuit.
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!ig"t dependent resistor L$% senses theillumination leel and gies the input signal as oltagedrop.
#mpli$er$arlington circuit ampli*es the input currentto get maimum current gain.
%witc" %elayswitch closes or opens electrically andautomatically, which is energi3ed or de energi3ed "ythe $arlington pair.
%treet lig"t Street light is the output of the circuit. !nthis circuit, it has "een replaced "y L1$
3.1.3 &' &(( control
#he circuit is switched ON or OFF "y the transistor in
saturation region or cut o) region respectiely, which is
controlled "y the signal from L$%. #he collector current
from the transistor toggle "etween ON or OFF modes.
3.2 Circuit Diagram
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-(!dentify all of the parts re5uired for all three circuits"ellow in the parts list6
/(Before starting ensure power supply is not connected
2(7se the Frit3ing Bread"oard Layout and Schematic$iagram images to connect the components with
prototyping wires to complete 8Circuit - 9 -:;%esistorotentiometer