Cabantog, Gerard John T.
ECE20L-2 / A1 / 2019151106
Activity 2
Introduction:
A diode is a di-electrode device that behaves as a one-directional switch. It allows current
from its anode to cathode terminal when it has forward bias. On the other hand, it has almost
zero current when it is in reverse bias. There are different types of semiconductor diodes, such
as: rectifier diode, Zener diode, light-emitting diode, Schottky diode, varactor diode, and other
kinds. In this activity, we are going to use the rectifier diode. Let us utilize the LTSPICE to run
simulations and determine the characteristics of rectifier diodes and their circuits.
Part 1: Semiconductor Diodes
Our objective is to be familiar with the different kinds of Semiconductor Diodes, before
proceeding with rectifier diodes.
1.1 Fill-up the Table 1. Write the application/s and attach a sample photo for each type of semiconductor
diode. Do not forget to indicate the source or website where we got the photos.
Table 1. Types of Semiconductor Diodes
Semiconductor Diode Application Sample Photo Source or website of photo
Rectifier Diode This are used for https://www.reichelt.com/pl/
converting AC to DC en/rectifier-diode-100v-10a-
in power supplies, a axial-nte-5812hc-
method called p219539.html
rectification.
Zener Diode This are used for the https://www.distrelec.biz/en/
maintenance of fixed zener-diode-3w-5v-1ua-do-
voltage. 41-rnd-components-rnd-
bzx85c7v5/p/30129873
Light Emitting Diode When an electric https://shopee.ph/75-x-
current travels 3mm-Red-Green-Yellow-
through them, they Assorted-Color-LED-Light-
emit light. Emitting-Diodes-
i.116320873.1824093019
Varactor Diode These are commonly https://www.electronicshub.
seen in radio org/varactor-diode/
frequency or RF
circuits to have
variable capacitance
regulated by voltage.
Schottky Diode Because of their low https://ph.rs-
power and high online.com/web/p/rectifier-
switching speeds, diodes-schottky-
applications include diodes/8062003/
rectification, signal
conditioning and
switching, through to
TTL and CMOS logic
gates.
Part 2: Characteristics of Rectifier Diode
Our objective is to simulate the characteristics of a Rectifier Diode by using the LTSPICE tool.
Here is a link about ‘Getting Started with LTSPICE.’
https://learn.sparkfun.com/tutorials/getting-started-with-ltspice/all
2.1 Connect the circuit diagram, as shown in Figure 1, in LTSPICE tool. The student or group may use
another kind of rectifier diode for diode D1, another value of resistance for resistor R1, and another
voltage level for dc voltage source V1. Take the photo of your own circuit diagram drawn in LTSPICE
tool, and place it in Figure 2. (One way to capture the screen in LTSPICE is: View > Paste Bitmap.)
Fig. 1. Diode Circuit (sample). Fig. 2. Connection of Diode Circuit.
2.2 Include a SPICE directive in your schematic diagram. In Figure 1, the directive is .DC V1 -100 100 1.
This directive describes the dc simulation, wherein the voltage of V1 will start from -100 V to +100 V
with an increment of +1 V. For your simulation, set the dc simulation from +200 V to -200 V with 1 V
increment. Run your simulation and show the waveform of current along diode D1. Figure 3 shows
the example of the simulation waveform for the diode circuit in Figure 1. In Figure 3, the current of
diode D1, I(D1), is in y-axis and the voltage of V1 is in x-axis. Now, take a photo of your own
waveform, and place it in Figure 4.
Fig. 3. I(D1) vs. V1 (sample). Fig. 4. Current along Diode D1.
2.3 Modify your simulation waveform. Display in the x-axis the voltage across the diode D1. In y-axis,
display the current along the diode D1. Take a snapshot of this waveform, and place it in Figure 5.
Complete the caption of Figure 5 by writing the part number of your diode D1. (Example: The part
number of diode D1 in Figure 1 is 1N914.)
Fig. 5. Current-Voltage Characteristics of Diode 1N914.
2.4 Based on the simulation results in Figure 4 and Figure 5, indicate in Table 2 the voltage and
current of diode D1.
Table 2. Current and Voltage of Diode 1N914.
Voltage of Bias V1 Voltage across Diode D1 Current along Diode D1
- 10 V -22.9977µV -2.5300018nA
-5V -22.952262µV -2.525008nA
0V 0V 0V
0.25 V 136.0463175mV 14.964935µA
0.50 V 272.092635mV 29.92987µA
0.75 V 408.1389525mV 44.894805µA
1V 544.18527mV 59.85974µA
5V 4.4480867V 489.38387µA
10 V 9.4145827V 1.0356135mA
2.5 Based on the simulation results, briefly explain how to turn on the diode?
It would appear from my model that if the diode D1 voltage is positive, then the diode can be described as current can pass
through as shown on the table.
2.6 Based on the simulation results, briefly explain how to turn off the diode?
Basically the diode D1 voltage is 0, so it can be described as off. This also pertains to the current that can move or flow
when the diode D1 voltage is negative, then it van be defined as off because no current can travel or flow.
Part 3: Half-Wave Rectifier
Our objective is to simulate the operation of a Half-Wave Rectifier circuit using the LTSPICE tool.
3.1 Connect in LTSPICE the circuit diagram of Half-Wave Rectifier in Figure 6. The student or group may
use another kind of rectifier diode for diode D1, another value of resistance for resistor R1, and
another voltage level for ac sine-wave voltage source V1. Take the photo of your own circuit
diagram drawn in LTSPICE, and place it in Figure 7.
Fig. 6. Half-Wave Rectifier (sample). Fig. 7. Connection of Half-Wave Rectifier.
3.2 Include a SPICE directive in your schematic diagram. In Figure 6, the directive is .TRAN 0.1. This
directive describes the transient simulation with a time stop of 0.1 second or 100 millisecond. The
resulting waveform in transient simulation is similar with the display of oscilloscope instrument,
wherein the x-axis is also time. In Figure 6, the input V1 is a sine-wave voltage source with 0 V dc
level, 10 V amplitude, and 60 Hertz frequency. With a time stop of 100 ms and with 60 Hz sine wave
input (16.67 ms period), the simulation results displayed 6 cycles as shown in Figure 8. For your
simulation, set the transient simulation to display 3 complete cycles. Run your simulation, and show
the waveforms of input voltage V1 and output voltage across R1. Figure 8 shows the example of
simulation waveforms for the half-wave rectifier circuit in Figure 6. Now, take a photo of your own
waveforms, and place it in Figure 9.
Fig. 8. Signals in HW Rectifier (sample). Fig. 9. Input and Output Voltages in HW Rectifier.
3.3 Based on the simulation results in Figure 9, determine the peak voltages of input voltage V1 and of
output voltage across resistor R1.
Vinput(max) = 9.9983592V. Voutput(max) = 9.3822217V
Briefly explain the discrepancy between the input voltage and output
voltage.
It would appear like the V input is not equivalent to the V output, which could be against the power
adaptor inefficiencies
3.4 Based on the simulation results in Figure 9, determine the frequency of input voltage V1 and of
output voltage across resistor R1.
frequency(input) 60Hz. frequency(output) =60Hz.
3.5 Briefly explain the operation of Half-Wave Rectifier.
In a half-wave rectifier circuit, load resistance is connected in series with the PN junction diode. The input of the half-wave
rectifies is an alternating current. A step down transformer takes an input voltage then the resulting output will be directed
to the load resistor and towards the diode.
Part 4: Full-Wave Rectifier
Our objective is to simulate the operation of a Full-Wave Rectifier circuit using the LTSPICE tool.
4.1 Connect in LTSPICE the circuit of Full-Wave Rectifier in Figure 10. The student or group may use
another kind of rectifier diode for diodes D1, D2, D3, and D4, another value of resistance for resistor
R1, and another voltage level for ac sine-wave voltage source V1. Take the photo of your own circuit
diagram drawn in LTSPICE, and place it in Figure 11.
Fig. 10. Full-Wave Rectifier (sample). Fig. 11. Connection of Full-Wave Rectifier.
4.2 Include a SPICE directive in your schematic diagram. For your simulation, set the transient
simulation to display 4 complete cycles. Run your simulation, and show the following waveforms:
current along diode D1; current along current D2; current along diode D3; current along diode D4;
input voltage V1; and output voltage across resistor R1. Take a photo of your waveforms, and place
it in Figure 12.
Fig. 12. Waveforms of Currents and Voltages in Full-Wave Rectifier.
4.3 Based on the simulation results in Figure 12, briefly describe which diodes turn on during the
positive half cycle of the input voltage and during the negative half-cycle of the input voltage.
Then it would appear like only the top diode is conducting and the bottom diode is blocking the current if
the voltage polarity is positive and negative on the top and bottom respectively. The first half of the sinus
wave is then seen by the load, which is positive on the top and negative on the bottom. The secondary
winding of the transformer's top half is the only one that holds the current throughout this half loop. The
AC polarity then reverses for the next half cycle in which the other diode and the lower half of the
secondary winding of the transformer bear the current while the segments of the circuit carry the current
idle throughout the last half cycle. Then the load sees half of a sine wave of the same polarity as before.
4.4 Based on the simulation results in Figure 12, determine the peak voltages of input voltage V1 and of
output voltage across resistor R1.
Vinput(max) = 9.9828626V. Voutput(max) = 9.3874218V
Briefly explain the discrepancy between the input voltage and output
voltage.
As before, due to the inefficiencies in the power adaptor, V input and V output are not comparable.
Cabantog, Gerard John T.
ECE20L-2 / A1 / 2019151106
SEMICONDUCTOR DIODES
4.6 Based on the simulation results in Figure 12, determine the frequency of input voltage V1 and of
output voltage across resistor R1.
frequency(input) =60Hz. frequency(output) = 60Hz
4.7 Briefly explain the operation of Full-Wave Rectifier.
Full wave rectifier includes a transformer tapped to the top of it, which results in equivalent voltages both above and
below the center tap. A positive voltage occurs on the anode of diode 1 during the positive half-cycle, while a negative
voltage occurs on the anode of diode 2 during the negative half-cycle and is thus biased forward. It ends in a current
from diode through the load and a negative voltage occurs on the anode of diode 1 at the same moment, which in turn
biases it in reverse and thus does not work.
