Daniel Benjamin

1
Precision
Full-Wave Rectifier
Group 3
Daniel Benjamin
Steve Hamilton
Todd McKeehan
2
Presentation Outline

• Project Organization
• Circuit Schematic and Function
• Initial Circuit Behavior
• Problems with Initial Circuit
• Solutions/Circuit Design Changes
• Corrected Circuit Behavior
• Project Accomplishments

3
Budget
4
Equipment Price References

• Voltmeter-www.centralhobbies.com/Electrical/batter
  y_testers/vlt mtr.html
• Oscilloscope-www.webtronics.com/csi20dutrosw.html
• Spectrum Analyzer-www.metrictest.com/
  product_info.jsp?mfgmdl ADV20R3131A
• Function Generator-www.tequipment.net/
  InstekGFG3015.html
• Opamp-www.national.com/pf/LM/LM741.htmlAvailabili
  ty
• Diodes-

5
Gantt Chart
6
Rectifiers 101

• Full wave rectifier consists of a half wave
  rectifier and a summing amplifier.
• It operates by producing an inverted half-wave
  rectified signal and then adding that signal at
  double amplitude to the original signal in the
  summing amplifier.
• If you want the final output to be positive
  instead of negative for example merely reverse
  the two diodes in the half-wave rectifier section.

• Full wave rectifier- rectifier that converts the
  negative half wave of an alternating current into
  a positive half wave.
• Rectifier- electrical device that transforms
  alternating current into direct current.
• In other words, the half wave rectifier only
  keeps parts of the original input signal that
  were positive (or negative), but the full wave
  rectifier takes this farther by taking BOTH
  halves of the input signal and renders them both
  with the same output polarity.

7
Final Schematic
8
Measured
After
9.76 k
_
Values
19.51 k
9.75 k
_
9.76 k
Before
7.84 k
_
19.52 k
11.77 k
7.82 k
_
7.79 k

• Diodes
• 0.263 V
• 0.265 V

• Diodes
• 0.563 V
• 0.570 V

19.9 k
9
(No Transcript)
10
Max1 (input peak)
11
Max2 (rectified peak)
12
Min1
13
Min2
14
Max(input)
Maxima
vs.
Frequency
Max2
Max1
15
Min(input)
Minima
vs.
Frequency
Min2
Min1
16
The Problems

• Rectifier did not work at higher frequencies than
  about 2kHz. (Circuit Problem)
• Circuit seemed to distort the input wave on the
  output. (ELVIS Problem)

17
The Solutions

• ELVIS Problem
• Proof that it was not our circuit, but ELVIS
  itself making the mistakes.
• Circuit Problem
• First we tried changing the resistor values in
  P-Spice.
• After some deductive reasoning we concluded that
  the diodes were at fault.

18
Problems with NI ELVIS

• ELVIS Function Generator DC Offset
• ELVIS Function Generator Waveform Distortion

19
ELVIS DC Offset
The Problem

• Maxima at 742.19 mV
• Minima at
• -1060 mV
• Offset
• -158.9 mV
• Adjustment
• 0.16 V

Waveform at 0 V DC offset 1kHz
20
ELVIS DC Offset
Sample Offset Values
21
ELVIS DC Offset
Sample Offset Values
22
ELVIS DC Offset
Sample Offset Values
23
ELVIS DC Offset
Sample Offset Values
Frequency 1 kHz Offset -2.00 V
Frequency 1 kHz Offset -1.00 V
24
ELVIS DC Offset
The Solution

• Offset
• -158.9 mV
• Adjustment
• 0.16 V

Waveform at 0.16 V DC offset 1kHz
25
ELVIS Waveform Distortion

• Input Waveform From NI ELVIS
• Input Waveform From Discreet Function Generator

Frequency 1kHz Amplitude 1 V
26
Circuit Problem

• Changing the resistor values proved to be useless
  in higher frequency operation.

R
R/2
27
200 and 400 Ohm
28
200 and 400 Ohm
29
250 and 500 Ohm
30
250 and 500 Ohm
31
250k and 500k Ohm
32
250k and 500k Ohm
33
Compare the Difference of the
Input/Output Waveforms with the
New Diodes and the Old Diodes.
34
Differences of the Two Diodes

• Compare the difference of the input/output
  waveforms with the new diodes and the old diodes.
• New diode is a XD-1442
• Has a .2 V voltage drop
• Old diode is a 4004
• Has a .6 V voltage drop

35
Old diode(4004) at 500 Hz
36
New Diode(XD-1442) at 500 Hz
37
New Diode(XD-1442) at 1 kHz
38
Old diode(4004) at 5 kHz
39
New Diode(XD-1442) at 5 kHz
40
Old diode(4004) at 10 kHz
41
New Diode(XD-1442) at 10 kHz
42
Old diode(4004) at 1 kHz
43
Old diode(4004) at 15 kHz
44
New Diode(XD-1442) at 15 kHz
45
Old diode(4004) at 20 kHz
46
New Diode(XD-1442) at 20 kHz
47
Primary
Project Accomplishments

• Precision Full-Wave Rectifier Using
  Operational Amplifiers
• ( Tested Range 1Hz to 20kHz)
• Pspice Experience
• NI ELVIS/LabVIEW Experience
• Discreet Instrument Experience

48
References
http//www.play-hookey.com/analog/full-wave_rectif
ier.html http//www.national.com/ms/LB/LB-8.pdf
http//www.educatorscorner.com/media/Exp95j.doc h
ttp//www.allaboutcircuits.com/vol_6/chpt_5/4.html
http//www.ni.com/pdf/products/us/4daqsc199-201_E
TC_212-213.pdf http//www.mindspring.com/mperrin2
/fullwave.htm http//www.maintenanceresources.com
/ProductsShowcase/icscbt2.htmElectCD5
http//www.uoguelph.ca/antoon/gadgets/741/741.ht
ml http//www.dca.fee.unicamp.br/courses/EE531/1s
2004/datasheet/1N4001_1N4007.pdf
http//www.swarthmore.edu/NatSci/echeeve1/Class/e
72/E72L3/Lab3(Diodes).html http//en.wikipedia.org
/wiki/P-n_junction BK PRECISION Instruction
Manual DMM 2707A http//www.web-ee.com/Downloads/S
imulator/simulation.htm http//www.orcad.com/prod
ucts/pspice/default.asp Weekly Presentations 1
through 4