AC to DC Rectification
and Power Supply
David Dwyier, Kyle Kingsborough, Pat Nadolny, Tom Ware
Intro
•  Problem
•  Bridge Rectifier
•  Low Pass Filter
•  Ripple Factor
•  Mathematical Model
•  LED Troubleshooting
•  Component Spec. List
Problem
•  Grid supplies alternating current but most
devices are powered by direct current
o
o
o
o
Bridge rectifier and filter
3.3 V across 1KΩ load
Supply: 10 V peak to peak A.C. sinusoidal signal
(7.07 Vrms) at 60Hz
LED indicator light turns on at 3.1 V D.C.
Bridge Rectifier
•
Half Wave
o
1 diode
o
positive wave passed and negative
blocked or vice versa
o
More ripple
•  Full Wave
o
o
o
4 diodes
Converts whole
wave to positive or
to negative
Less ripple
Bridge Rectifier (Full Wave)
•  4 Diodes
•  Converts AC to DC
•  Same polarity output for
either polarity input
Low Pass Filter
•  combination of a resistor in series with a load and
•
•
•
capacitor in parallel with a load
stores energy as the voltage increases
discharges energy once the voltage decreases
maximizes the voltage output to the source
Ideal Low Pass Filter
Ripple Factor
•  Undesirable
•  Compares the
ripple voltage to
the desired DC
voltage across
the load
Mathematical Model
Model Equation
Capacitor Value
Time Constant
•  Time Constant of 3.3E-5s
•  Steady State at 1.665E-4s
LED Troubleshooting
•  Addition of LED reduced potential across
load (2.6 V) by reducing current to load.
•  Another resistor (110Ω ) added to account
for new current draw from LED
Component Spec. List
Diodes - 1V forward bias voltage
Capacitor- 33µF
Resistors- 1Ω, 1 kΩ, 110Ω
Light Emitting Diode- 2V forward bias voltage
Schematic
u
Thank You
Questions?
References
•  http://sub.allaboutcircuits.com/images/22026.png
•  http://www.otherpower.com/rectifiers/image002.jpg
•  http://4.bp.blogspot.com/-49FIs-XuImY/TuE8R-xzCpI/
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AAAAAAAACzU/ix0Y2FR24zs/s1600/ccc123.jpeg
http://www.reuk.co.uk/OtherImages/
bridgerectifier.gif
http://www.electronics-tutorials.ws/diode/
diode14.gif