EGRE 224 - Microelectronics

EGRE 224 – Microelectronics
Diodes Circuit Designs
Jose Ramirez
Quan Ma

EGRE 224 (002) Lab – Diode Circuit Designs Jose Ramirez
Wednesday Quan Ma
Page 2 of 22
Introduction:
The purpose of this lab is to design and implement five circuits using actual components
diodes (1N4001GP) specifically, resistors, and capacitors provided. Given an open choice from a
specified select few resistors and capacitors to create each circuit. A Half-Wave Rectifier, a Peak
Rectifier, a Negative DC Restorer, a Voltage Doubler, and a Voltage Tripler are implemented.
Several tests are performed to determine the correct design of each circuit. After careful
gathering of data using the PXI systems oscilloscope, function generator, and the aid of
multisim. The results are compared with theoretical findings to ensure that the each circuit
built is working to specification and solves the problem at hand.
Background and Theory:
5 circuits Designs:
Part 1: Consider a half wave rectifier. A half-wave rectifier utilizes the positive side of a
sinusoidal signal. This is due to the fact that it contains a diode which acts as a one way valve.
Thus creating an output signal which only highlights the positive side of the sinusoidal input.
Figure 1 shows how a halve wave rectifier may be implemented.
Figure 1: Half wave rectifier implementation using an (1N4001GP) diode and resistor
in series.
A Half-Wave rectifer highlights properties of a diode. As the input signal is positive the
output measured across the Ristor (R1) is inevitably positive. As the sinusoid drops to its
negative side current doesn’t flow any longer throught the circuit due to the diode and
therefore the negative side of the output shows to be truncated. Choosing the right value of
resistors does not affect the very nature of how a half wave rectifier displays its output signal,
but it helps to regulate the voltage peak of the output signal. Refer to Figure 2 for a better
illustration on how this works.

Wednesday Quan Ma
Page 3 of 22
Figure 2: Two Halve Wave rectifiers compared using different valued resistors. The table
below highlight the Voltage Peak for each of the circuits. V2, V3 for Circuit schematics 1 and 2
respectively.
Figure 3: Wave form displaying the half wave rectifier at different resistor values. V1 as the
sinusoidal input voltage source, V2 displaying the output of Circuit 1 , and V3 the output for
Circuit 2 in (Figure 2).
The diode shown in the schematic for the Half-Wave Rectifier in Figure 1 only allows
current to flow through one direction due to the properties of a diode. As can be seen from
Figure 3, The output waveform illustrates that V2 is less than the voltage peak of V3 due to a
higher resistance, less current will flow through the diode, using the properties of the diode we
may calculate its current using the following equation, .
Similarly lowering the current means lower voltage across the diode. Refer to the voltage and
current relationship of a diode below.
( )

Wednesday Quan Ma
Page 4 of 22
For each of the circuits 1 and 2 in Figure 2 above we may calculate the voltage and current
relationship. Due to the fact that there is a lower voltage drop through the diode, the output
voltage will be greater.
( )
Modeling the diode as a rating of 1mA at 0.7V and VT = 0.0259V at room temperature.
( )
Using these theoretical findings one may proceed to model a desired Half-Wave rectifier with
precise voltage output peak.
Part 2: Consider a peak rectifier. A peak rectifier circuit consist of a capacitor and diode placed
in series. As one would expect a capacitor to behave, once the sinusoidal signal is turned on the
capacitor in the circuit will charge up during the positive cycles of the signal voltage, and it will
discharge when the signal voltage becomes negative.
Figure 4: Peak Rectifier Circuit modeled using a Diode (1N4001GP) and a 1uF capacitor in
Series with a 15kΩ resistor.
Do to the fact that the diode is connected in series with the voltage source and the
capacitor. As the sinusoid switches to its negative side, the diode becomes an open circuit and
the capacitor discharges but is not able to fully discharge quickly. This causes a smooth slow
discharge of capacitor voltage that pulses as the sinusoidal periods happen through time. This
creates the iconic output voltage for a peak rectifier circuit Illustrated in Figure 5 on the
following page.

Wednesday Quan Ma
Page 5 of 22
Figure 5: Waveform of Peak Rectifier Showing the input signal V1 and output V3
Figure 6: Capacitor and resistor in series for the peak rectifier
As can be seen the capacitor connected in parallel with the 15kΩ resistor shown in
Figure 6 above displays a peak rectifier. A half-wave rectifier with a filter capacitor acts like a
back-up battery. As the voltage reaches at its peak, it is charging the capacitor. Then as the
voltage peaks and starts to drop off, the capacitor discharges and fills in the gap for the power
failure and will charge up again as the voltage reaches to the highest peak again.
Using these theoretical findings one may proceed to model a desired Voltage Peak rectifier.

Wednesday Quan Ma
Page 6 of 22
Part 3: Consider a Negative DC Restorer otherwise known as a clamped capacitor Illustrated by
Figure 7 below. Due to the fact that the voltage of the capacitor seen in Figure 7 is charged and
a diode only conducts when the input is positive. The negative side of the square signal is
“clamped” by the capacitor. Refer to Figures 8 to Figure 9 for a visual representation on the
theory behind the Negative DC restorer and how one may implement and know a working
circuit is at hand.
The purpose of a clamped capacitor is to supply an output voltage that is greater than
the input voltage by manipulating the placements of diodes and capacitors. Figure 7 below
displays a Negative DC Restorer having a 2.5V peak 100 Hz square wave input signal connected
in series with a capacitor and a diode.
Figure 7: Negative DC Restorer (Clamped Capacitor) implemented using
a Square signal of -2.5V to 2.5V , 1uF Capacitor, and a (1N4001GP) diode in series.
Figure 8: Clamped Capacitor Circuit demonstrating the behavior of the circuit when the
positive side of the sinusoidal signal is highlighted, arrows illustrate the direction of the
current.
As can be seen by Figure 8, during this stage from when the input voltage is turned on.
The capacitor is slowly charged up from the positive side of the sinusoidal signal to 2.5V. The
capacitor holds this charge till the capacitor act as an open circuit leaving no current flowing
through the circuit, it will then contain a net voltage charge of 0V since polarities of the
capacitor and the input signal can be modeled using the relationship equations below. Where Vi
is the input voltage and Vc is the voltage across the capacitor. Giving Vo, as the output signal.
Following Kickoffs voltage law. The net voltages through the circuit must be equal to zero.

Wednesday Quan Ma
Page 7 of 22
Figure 9: Clamped Capacitor with negative input signal
As the polarity switches to the negative side of the input signal, shown in Figure 9. The diode
and its properties do not allow negative current to flow thus making the diode act as an open
circuit. Since there is no current flow, the capacitor cannot discharge. This means that the
capacitor will continue to stay fully charged having the output voltage at -5V. Seen with the
following equation below. Since we have the input voltage and the voltage from the capacitor it
must equal the output voltage of the circuit. Since the square signal is now at the negative side
current flowing the opposite way causing the diode to act as an open circuit essentially
“Clamping” the negative voltage on the capacitor , -5V. See equations below and waveform
Figure 10 for visual representation on how a negative Dc clamper is to behave.
Figure 10: Waveform for Negative DC Restorer (Clamped Capacitor)
Showing input waveform V1 and output waveform V2

Wednesday Quan Ma
Page 8 of 22
Part 4: Consider a Voltage Doubler. As can be seen, Figure 11 illustrates a basic setup on how a
Voltage Doubler may be implemented. The circuit consists of two diodes (both 1N4001GP) ,
two capacitors , and an input sinusoidal signal with a peak to peak voltage of 2.5V. At is
simplistic terms the voltage doubler in Figure 10 outputs a DC voltage equal to the peak-to-
peak value of the sinusoidal input. In other words, the circuit effectively doubles the input
voltage by with use of this diode and capacitor setup.
Figure 11: Schematic illustrating a Voltage Doubler.
Utitlizes a two 1uF capacitors and two (1N4001GP) diode pair.
Figure 12: Voltage Doubler displaying oscillating current flow throughout the circuit
Circuit1 - Illustrated on the left shows the current flow during its Negative Cycle
Circuit 2- Illustrated on the right shows the current flow during its Positive Cycle
Followed by Figures 11’s corresponding circuits above, displays the direction of the
current flow through the circuit is displayed. When the input AC source is supplying negative
voltage (circuit1) ,diode D3 turns off, leaving no current flow through the capacitor C2 whereas
the diode D2 turns on as capacitor C1 is being charged by the input signal. As the input signal
continues to oscillate, the capacitors charge until capacitor C1 maximizes its charge to 2.5V.
Alternatebly, when the signal on the sinusoid becomes positive, diode D2 is reverse biased
blocking the discharging of C1 while diode D3 is forward biased charging up capacitor C2. But
because there is a voltage across capacitor C1 already equal to the peak input voltage, capacitor
C2 charges to twice the peak voltage value of the input signal. Then capacitor C1 and the input
AC voltage can supply capacitor C2 5V. This phenomenon that happens with the circuit, can be
modeled by an output signal illustated by Figure 13 on the following page.

Wednesday Quan Ma
Page 9 of 22
Figure 13: Wave form illustrating the voltage doubler that illustrates twice its input voltage
peak for its output voltage ie: Vout = 2Vpk
Due to the fact that the input voltage is an AC signal and would not behave
instantaneously. The charge of the capacitor would not fully be charged at the initial voltage
peak of the input source. The voltage will increase slowly on each input cycle, in terms as time
advances the DC output will eventually settle at 2 times the peak input Voltage Peak. Given the
fact that C2 only charges up during one half cycle of the input waveform, the resulting output
voltage has a ripple effect that slowly increases as time advances. Figure 14 Below illustrates
this looking at the waveform closer to the peak voltage of the sinusoidal signal.
Figure14: Cursor and zoomed in Output Waveform of Figure 12 that illustrates a closer look of
the input and output signal of a Voltage Doubler. Where V1 shows the input sinusoidal signal
and the output is shown demonstrated by V3 of the waveform.

Wednesday Quan Ma
Page 10 of 22
The voltage of the input AC source only reaches its peak in nanoseconds such that the
capacitor does not have enough time to fully charge. When the input signal reaches back to
greater than or equal to 0.7V, enough to turn the diode back on, the capacitor will continue to
recharge as the input signal continues to oscillate until the output voltage approximately
doubles its highest peak in voltage of to, what would be in for this case 5V.
Part 5: Consider a Voltage Tripler. As can be seen, Figure 15 illustrates a basic setup on how a
Voltage Tripler may be implemented. The circuit consists of three diodes (all 1N4001GP) , three
capacitors , and an input sinusoidal signal with a peak to peak voltage of 2.5V. At is simplistic
terms the voltage tripper in Figure 15 outputs a DC voltage equal to the peak to peak value of
the sinusoidal input and an additional 2.5v due to an additional capacitor added to the circuit.
In other words, the circuit effectively triples the input voltage with use of the diode and
capacitor setup illustrated below Figure 1.
Figure 15: Schematic illustrating a Voltage Tripler.
Utitlizes a three 1uF capacitors and three (1N4001GP) diodes.
Figure 16: Voltage Tripler displaying oscillating current flow throughout the circuit
Circuit1 - Illustrated on the left shows the current flow during its Negative Cycle
Circuit 2- Illustrated on the right shows the current flow during its Positive Cycle

Wednesday Quan Ma
Page 11 of 22
Shown in Figure 16 above illustrates , the arrows display the direction of the current
flow through the circuit. When the AC source is supplying positive voltage, current flows
through diode D3 and diode D4 having the capacitors charge up. However, diode D2 will not
turn on and will act as an open circuit because diode D2 will not allow negative current flow. If
however, D2 had changed directions, D2 would allow current to flow. As the AC source
oscillates to supply negative voltage, diode D2 turns on approximately 0.7V and the rest of the
diode does not allow current flow in the opposite direction and acts as an open circuit as shown
in Figure 16 circuit 2. During these oscillations, on the negative input voltage cycle, capacitor C1
and C2 charges through the DC restorer until it reaches to the peak of the input signal at 2.5V.
During this cycle the charge of capacitor C3 cannot dissipate since the diode D4 will not allow
current flow. On the positive cycle, the charge on capacitor C1 is replenished and adds up with
the input signal in series which is twice the input voltage peak. With the aid of capacitor C2, has
a voltage drop of approximately 5V supplies the voltage to C3 having V3 = -5V. Using the
relationship between the voltages charges of the capacitors the equation
( ) ( ) ( ) . Then capacitor C1, C2, and the input AC voltage can
supply capacitor C3 for a total votlage output of roughly 7.5V, effectively tripple the input
vorlage of 2.5v . This phenomenon that happens with the circuit, can be modeled by an output
signal illustated by Figure 17 below.
Figure 17: Wave form illustrating the voltage tripler that illustrates triple its input voltage
peak for its output voltage ie: Vout = 3Vpk

Wednesday Quan Ma
Page 12 of 22
Due to the fact that the input voltage is an AC signal and would not behave
instantaneously. The charge of the capacitor would not fully be charged at the initial voltage
peak of the input source. The voltage will increase slowly on each input cycle, in terms as time
advances the DC output will eventually settle at 3 times the peak input Voltage Peak. Given the
fact that C3 only charges up during one half cycle of the input waveform, the resulting output
voltage has a ripple effect that slowly increases as time advances. Figure 17 on the following
page illustrates this looking at the waveform closer to the peak voltage of the sinusoidal signal.
With the same concept as the voltage doubler, a Voltage Tripler that has three times the peak
voltage input. The voltage tripler has an additional diode and capacitor compared to the voltage
doubler where the variations of the circuit design affect the voltage output. Notice that the
output waveform is measuring the output voltage of V(1)-V(3). The reason for this is because
the capacitor C2 is not where the voltage is tripling, rather it is between the input voltage and
the voltage across the diode D3.
The voltage of the input AC source only reaches its peak in nanoseconds such that the
capacitor does not have enough time to fully charge. When the input signal reaches back to
greater than or equal to 0.7V, enough to turn the diodes back on, the capacitors in the circuit
will continue to recharge as the input signal continues to oscillate until the output voltage
approximately triples its highest peak in voltage of to, what would be in for this case 7.5V.
Procedure: To begin with the prototyping of each of the circuits designed in theory. Once the
components were selected, the circuits were implemented on a bread board using actual
components diodes, the (1N4001GP) specifically, resistors, and capacitors. For The Design of
the Half-Wave Rectifier, Peak Rectifier, Voltage Doubler, and Voltage Tripler, a the function
generator used for the experiment was set to Sinusoidal waveform of Amplitude 2.5(p-p) was
used. As for the design for the Negative DC Restorer a Square wave input Signal was used. Each
of the signals were set to a frequency of 100Hz.
After the circuits were created and tested on Multisim and confirmed working using
transient analysis simulations to obtain desired outputs. The circuits were built on a breadboard
using selected resistors, capacitors, and diodes provided by the instructor. Figures 18-22
illustrate views of how each circuit was implemented, connected, and measured using actual
components on a breadboard, function generator, and oscilloscope. Outputs where not
measured at the same time for each circuit. Figures 18-22 simply illustrates how the
oscilloscope connections are placed on each of the circuits to measure that the desired output
was obtained and the circuit behaved as intended.

Wednesday Quan Ma
Page 13 of 22
Figure 18: Half Wave Rectifier illustrating how the function generator (XFG1)
and oscilloscope (XSC1) were connected to the circuit to gather data about the circuit.
Part I: After performing a Transient analysis to figure out the voltage output and behavior the
circuit design. Prototyping was done by adjusting and capturing the input and output signal for
the function generator (XFG1) to a frequency of 100Hz with an amplitude of 2.5V peak to peak.
XFG1 and XSC1 illustrate the function generator and oscilloscope respectively used to measure
the input and output, Vin and Vout. Taking measurements on the half wave rectifier designed
were done in precisely the same fashion illustrated in Figure 18. Data was recorded and results
were gathered to be analyzed and compared with theoretical findings.
Figure 19: Peak Rectifier circuit diagram illustrating how the function generator (XFG1)
and oscilloscope (XSC1) were connected to the circuit to gather data about the circuit.
Part II: After performing a Transient analysis to figure out the voltage output and behavior the

Wednesday Quan Ma
Page 14 of 22
Figure 20: Negative DC Restorer (Clamping Capacitor) Circuit diagram illustrating how the
function generator (XFG1) and oscilloscope (XSC1) were connected to the circuit to gather
data about the circuit
Part III: After performing a Transient analysis to figure out the voltage output and behavior the
the input and output ,Vin and Vout. Taking measurements on the half wave rectifier designed
Figure 21: Voltage Doubler Circuit diagram illustrating how the function generator (XFG1) and
oscilloscope (XSC1) were connected to the circuit to gather data about the circuit
Part IV: After performing a Transient analysis to figure out the voltage output and behavior the

Wednesday Quan Ma
Page 15 of 22
Figure 22: Voltage Tripler Circuit diagram illustrating how the function generator (XFG1) and
oscilloscope (XSC1) were connected to the circuit to gather data about the circuit
Part IV: After performing a Transient analysis to figure out the voltage output and behavior the

Wednesday Quan Ma
Page 16 of 22
Experimental Results: Below shows the results for the experiment performed.
Par1: Half-Wave Rectifier Circuit
Figure 23: Screenshot of PXI Oscilloscope readings for the Half-Wave Rectifier Design
Operating a frequency of 100Hz and an Amplitude of 2.5V p-p
Cursors highlighting each signals peak value.
Cursor zero: mag Input Signals Peak Value of Vin=2.49V
Cursor one: mag Output Signal Peak Value of Vout = 2.03V , as can be seen from the output
signal the negative output of the signal is truncated. Only half of the wave is rectified.
This is illustrated by the Experimental design using a 15kΩ in series with a 1N4001GP diode as
can be seen in Figure 1.

Wednesday Quan Ma
Page 17 of 22
Par2: Design for Peak Rectifier
Figure 24 : Screenshot of PXI Oscilloscope readings for the Peak Rectifier Design Operating a
frequency of 100Hz and an Amplitude of 2.5V p-p
Cursor one: mag Output Signal Peak Value of Vout = 1.98V
This is illustrated by the Experimental design in Figure 4.

Wednesday Quan Ma
Page 18 of 22
Par3: Negative DC Restorer (Clamped Capacitor Circuit)
Figure 25: Screenshot of PXI Oscilloscope readings for the Negative DC Restorer Design
Operating a frequency of 100Hz and an Square Wave Amplitude of 2.5V p-p
Cursor one: mag Output Signal Peak Value of Vout min= -4.69V and Vout max= 390.76mV
This is illustrated by the Experimental design as can be seen in Figure 6.

Wednesday Quan Ma
Page 19 of 22
Par4: Design of Voltage Doubler
Figure 26 : Screenshot of PXI Oscilloscope readings for the Voltage Doubler Design Operating
a frequency of 100Hz and an Amplitude of 2.5V p-p

Wednesday Quan Ma
Page 20 of 22
Par5: Design of Voltage Tripler
Figure 27 : Screenshot of PXI Oscilloscope readings for the Voltage Tripler Design Operating a
frequency of 100Hz and an Amplitude of 2.5V p-p

Wednesday Quan Ma
Page 21 of 22
Summary/ Conclusions:
For part 1, the oscilloscope displayed in Figure 1 is behaving as a half-wave rectifier simulated in
Figure 3. This proves that the diode placed in series with the resistor and the input signal would allow
current to flow one way depending on the orientation of the diode. However one difference between
the two is the calculations of the max peak voltage of the output. It was predicted that there was going
to be a 0.645V through the diode, meaning that there should have been a max peak of approximately
1.86V as the output. . The reason for this is the components have an exact value
and measuring only the resistor can be directly measured and the diode rating cannot be measured.
Also, the oscilloscope has a slight error in measuring and will not output the correct results as close as
the simulation transient analysis.
Part 2, the oscilloscope displayed in Figure 4 is behaving as a peak rectifier where the circuit is a half-
wave rectifier and includes a capacitor in series with the resistor. This means that the capacitor will be
charged from the input signal. As soon as the voltage drops from the input, the capacitor still has its’
charge and dissipates until the input voltage is higher than the voltage the capacitor has left. This makes
the sinusoidal voltage wave look closer to a DC voltage. The max output voltage displays that it is
reaching at the same peak as the input voltage. This is because the settings of the oscilloscope Volts/Div
channel 0 and channel 1 are different. Channel 0 doubles channel 1. From the measurement settings, it
displays that the max voltage output is 1.98V and the max voltage input is 2.48V. This is close to the
simulation displayed in Figure 5 having an output voltage of 2.18V and an input 2.48V. Thus the
difference between the simulated and the experiment results are calculated shown below.
| |
For part 3, the Originally the resistor was not added in Figure 7 which the output is closer to the ideal
value of -5V for the negative DC restorer (clamped capacitor). However, for the experiment, there was a
discrepancy in measuring the output voltage. From part 2, the diode and the capacitors are swapped,
meaning that the output voltage cannot be measured through the diode. Therefore, a resistor must be
added in parallel with the diode in order to measure the output voltage across the diode. As for the
comparison between the simulation and the results, the simulation displayed in Figure 8 the voltage min
is -4.91V and the max output 100mV. This experimental output voltage peak shown Figure 25 is -4.69V
with a percent difference calculated below.
|
( )
|
For part 4, the voltage doubler simulation has a 4.65V Figure as the output compared to the experiment
having 3.90V Figure. The percent difference is calculated below:
| |
There is a larger difference between the two because the voltage doubler deals with more diodes and
capacitors such that there is more room for error when making measurements. Also, it was measured
using the oscilloscope which is not as accurate as using a Digital Multimeter.

Wednesday Quan Ma
Page 22 of 22
For part 5, the voltage tripler simulation has a 6.99V Figure 11as the output compared to the
experiment having 5.79V Figure . The percent difference is calculated below:
| |
Just like the doubler, there is a larger room for error when dealing with more diodes and
capacitorsThere is a larger difference between the two because the voltage doubler deals with more
diodes and capacitors such that there is more room for error when making measurements. The reason
as to why the simulations was a bit off from the experimental results is due to the fact that the capacitor
values is slightly lower from the capacitor values used in simulation. This was okay due in theory the
voltage doubler and Tripler differ and had such big percent difference but the theory is illustrated in the
experimental results that the doubler and Tripler work and the results from the experiment complement
the theoretical findings.
Overall, it was noticed that for each part of the simulation and the experiment is what leads up
to the voltage tripler. Part 1 starts with a rectifier showing that the negative current flow can be blocked
from connecting the input AC signal in series with a diode and a resistor, having the resistor measuring
the output voltage. Part 2 is just like part 1 except the resistor is now replaced with a capacitor. From
the waveform, this stabilizes the voltage drop from the charge that dissipates from the capacitor and
starts to mimic a DC input signal. Part 3 switches the placement of the capacitor and the diode from part
2, displaying that the output voltage could surpass the peak input voltage from an AC source by having
the capacitor “clamped”. Part 4 is a continuation from part 3 and part 2 combined into one circuit in
order to double the output voltage. With knowing the input voltage can double from using the peak
rectifier and the DC restorer, manipulating all of the circuit design can implement a voltage Tripler. This
proves that the voltage from an AC source does not need to be increased in order to have a higher
output voltage.

EGRE 224 - Microelectronics

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to EGRE 224 - Microelectronics

Similar to EGRE 224 - Microelectronics (20)

EGRE 224 - Microelectronics