25-04-2010, 08:47 PM
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ULTRASONIC LAMP BRIGHTNESS CONTROLLER
Presented By :
P.V.S.Chaitanya (2006EEE040)
D.V.Subrahmanyam (2006EEE058)
M.Ravi (2006EEE028)
P.Lokesh (2006EEE035)
Under the esteemed guidance of
Ch.Das Prakash, M.Tech.
Assistant Professor.
OBJECTIVE
Remote control of AC voltage by phase control of a silicon controlled rectifier (SCR) in a simple and easy way at low cost.
INTRODUCTION
Transmitter circuit generates ultrasonic sound waves of 40-50kHz frequency.
The receiver senses the ultrasonic sound from the transmitter and enables a unijunction transistor (UJT) based relaxation oscillator.
phase control of silicon controlled rectifier controls the lamp brightness.
BLOCK DIAGRAM:
TRANSMITTER CIRCUIT:
RECIEVER CIRCUIT
RECIEVER CIRCUIT
Components:
40 kHz Ultrasonic reciever
BC549C npn transistor
CA3140 Operational Amplifier
CD4017 Decade Counter
2N2646 UJT
TYN6004 SCR
9.1 V Zener Diode
Diode Bridge
BLOCK 1: AMPLIFIER CIRCUIT
BC549C
NPN transistor.
Used for amplification and switching.
Max : 45v;100mA;
Advantages of CE Configuration:
High gain
High input impedance
two Npn transistors are used for amplification in CE configuration
T1 amplifies the signal given , output is given to T2 for further amplification
BLOCK 2: FILTER & RECTIFIER CIRCUIT
BLOCK3 : COMPARATOR CIRCUIT
CA 3140 OP AMP
gate protected MOSFET (PMOS) transistors in the input circuit
rectified input: 2;
Reference input: 3
Vdd: 7
Gnd: 4
Output: 6
Inverting comparator as schmitt trigger with Positive feed back
Advantages of positive feed back :
High switching speed.
False transition due to noise
can be eliminated
BLOCK 4: DECADE COUNTER
IC4017B - 5-stage Johnson counter
TIMING DIAGRAM:
BLOCK5: PHASE CONTROL CIRCUIT
2N2646 UJT:
Features:
Low power consumption.
Reliable fast operation.
BLOCK6: Power Circuit
AC mains is recitified by diodes D13 through D16 and limited to 9.1V by using zener diode ZD1.
APPLICATIONS:
The circuit can be used as power controller in
Lighting Equipment,
House hold appliances
Single-phase AC Motor
Heater , etc
CONCLUSION & SCOPE
our project is a simple way of wire less AC voltage control at low cost.
It can be extended to high rating operations.
Can be Extended and applied where the size of AC voltage control operation is an important aspect.
REFERENCES:
DIGITAL CIRCUIT DESIGN “ Marris Mano
POWER ELECTRONICS “ P.S. Bhimra
LINEAR INTEGRATED CIRCUITS “ Ramakanth A. Gaykwad
Wikipedia.org;
Datasheets of CA3140, 2N2646, CD4017, CD4001B
QUERIES???
