ITLPUBLICSCHOOL
PHYSICS PROJECT FILE
To construct a Full Wave Bridge rectifier
and show that the (AC) alternating current is
rectified into a direct current (DC).
PRATHAM SANGWAN XII B
Acknowledgement
The project could have never been possible without
the support of various sources. It is extremely
impossible to thank every individual who has helped
me in completing this project. Some people have
helped in the basic formularization and there were
sources that helped me in giving the ideas a physical
form/shape.
I am extremely grateful to my mentor, Mrs. Seema
Sachdev for her invaluable guidance in the project
right from the beginning. Her vital support helped
the project to take a logical and suitable shape. I
take this opportunity to thank the School
authorities, for extending their full support and
cooperation in the project. Last but not the least; I
would like to thank everyone who has offered a
helping hand when required.
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Certificate
This is to certify that Pratham Sangwan of class
XII-B has completed the project titled “To
construct a Full Wave Bridge rectifier and show
that the (AC) alternating current is rectified into
a direct current (DC).”During the
academic year 2022-23 and submitted a
satisfactory report as compiled in the following
pages under the supervision of Mrs. Seema
Sachdev.
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INDEX
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
INTRODUCTION
Procedure
Observation and Data
Result / Inference
Precautions
Bibliography
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INTRODUCTION
 A rectifier is an electrical device that converts alternating
current (AC), which periodically reverses direction, to
direct current (DC), which flows in only one direction. The
process is known as rectification. Rectification produces a
type of DC that encompasses active voltages and
currents, which are then adjusted into a type of constant
voltage DC, although this varies depending on the
current's end-use The current is allowed to flow
uninterrupted in one direction, and no current is allowed
to flow in the opposite direction. Physically, rectifiers
take a number of forms, including vacuum tube diodes,
mercury-arc valves, copper and selenium oxide rectifiers,
semiconductor diodes, silicon-controlled rectifiers and
other silicon-based semiconductor switches. Rectifier
circuits may be single-phase or multi-phase. Most low
power rectifiers for domestic equipment are singlephase, but three phase rectification is very important for
industrial applications and for the transmission of energy
as DC.
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PROCEDURE
 Take the transformer and attach it to one end of the
circuit board Attach the plug with the wire of desired
length and connect it to the transformer AC In now, take
four diodes and connect the 4 diodes into a loop Connect
the anode of diode D1 to the anode of D2- Connect the
cathode of D2 to anode of D3-connect the cathode of D3
to anode of D4 and connect the anode of D4 to cathode
of D1- The output of transformers should be connected
to A and C Now, take two capacitor and connect its -ve
terminal to (-)veand +ve terminal to +ve And connect
both the capacitors to B and D Connect a resistor and a
LED to the capacitor Attach wire from the capacitors
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OBSERVATION
 The thermistorusedisanegativetemperature
coefficient(NTC) resistor.
 The reason LED glows is that whenthethermistor is
heated,its resistance decreases due to which the base
voltage increases and the point comes when the base-
¬‐emitter junction is forward biased.
 As a result the transistor turns on and an output
current flows from its collector to the emitter, making
the LED glow.
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Results
 Thecurrent flowing in thecircuit is directly
proportional tothetemperature of the surrounding
because we have used an NTC thermistor in the
circuit where the resistance of thermistor is
inversely proportional to the surrounding
temperature in which the thermistor is kept.

Increase in base voltage results in the glow of
LED. To increase the base voltage we need to use
a variable resistor which can forward bias the
base-emitter junction of the transistor to initiate
the flow of collector current which makes LED
glow. Thus we use NTC thermistor to provide
variable resistance.
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Precautions
 Self-heating: Thermistors are not self-powered,
which means acurrent must pass through the
device to provide measurable voltage. The
current causes Joule heating withinthesensor.
 Self-heating will appear as a measurement
error. You mustmake sure to pay attention to
the magnitude of measurements of the current
supplied by the ohmmeter.
 As a result of construction, the thermistor is a bit
more fragile when compared to a thermocouple.
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BIBLIOGRAPHY
 Physics – Textbook for XII (NCERT)
 Modern’s ABC of Physics
 Laboratory Manual (Rachna Sagar Pub.)
 Encyclopedia
 Google.com
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