Electronics 1 Laboratory
EG3156
DATE OF EXPERIMENT: February 18th, 2019
DUE DATE OF REPORT: February 20th, 2019
N/A
BACKGROUND:
Study of the Art of Electronics Lab Manual, by Thomas C. Hayes, Paul Horowitz. Chapter 1 –
Overview, DC Circuits (Worked example: Resistor & instruments).
LIST OF EQUIPMENTS USED:
1.
2.
3.
4.
5.
6.
Breadboard,
Resistors, Capacitors, Inductor
Wires, Wire stripper, Needle nose plier,
V various cable set
Multimeter, Oscilloscope, function generator.
Transformer
OBJECTIVES:
The overall objective of this experiment was to familiarize ourselves with Half-wave, Full-wave Bridge
rectifiers Ripples, and different signal diodes. Through the completion of this experiment we were able to
gain a real-world view on how these different types of rectifiers work and to be able to differentiate all of
the different types of these as well as make different assessments for their uses.
Procedure:
1.) Half-wave Rectifier: For this part of the experiment we constructed the circuit as shown below using
a 6.3Vac (rms) transformer and a 1N914 diode. We then connected it to the scope. This was done in order
to observe the output.
Below is the data we achieved through the completion of this part of the experiment.
As you can see the original input going into our circuit had a much higher max voltage and amplitude
compared to what we originally had. This is because a specific voltage needed to be reached in order for
the diode to be turned on. When analyzing the waveform of the output compared to the input it can also
be noticed that all of the negative voltages were filtered out through the Half-Wave rectifiers, we
constructed this explains why the scope looked the way it did for this particular part of the experiment.
We found the rms to be 6.3 and Vmax to be that times the root of 2. We also found Vd to be 0.6 volts.
2.) Full-wave Bridge Rectifier: This next part of the experiment had us construct and work with a fullwave bridge rectifier as shown in the circuit below. We were specifically instructed not to connect both
the input and outputs of the circuits of the scope for this part in order to avoid problems with our circuit.
Below is the data and pictures we received from completing this part of the experiment
As you can see from the scope the full-wave bridge rectifier circuit is similar to the half wave circuit
except instead of just filtering out all of the negative voltage, all of the negative voltage is converted into
positive voltage. This can be seen when comparing the scope pictures here to the original input picture we
took in the first part of this experiment. The data we got from the full wave rectifier does actually make
sense and it was just like what we learned in the electronics class about them. If we simply had to work
with the AC current and voltage, there would be no sure way to utilize the voltage straight away like that
since we would be working with a equal positive and negative voltages that would cancel each other out.
The rectifiers make it possible for us to work with only positive voltages. When a diode fails it usually
fails closed due to overvoltage, this is why we were instructed not to connect input and outputs as to not
overload the scope. The flat regions are the spaces in the voltage change from pos to neg in which the
voltage is too small to power on the diodes. The duration we measured for this was 440 microseconds and
can be seen in our pictures of the scope.
3.) Ripple: The third part of the experiment had us working with the same circuit we used in part 2 of the
experiment the circuit shown below except this time we connected a 15 micro F capacitor across the
output. Observed the results on the scope, then took a 500 micro F capacitor and attached that to the end
of the circuit
.
Shown below are the pictures we took from our scope through the completion of this part of the
experiment.
From looking at the scope the outputs we got do make sense, looking back at the pictures and data we got
from completing part 2 of the experiment and comparing them to what we got here it is simple and easy to
see that the capacitors job in this specific circuit is to try and keep the voltage much more constant than it
was before when we worked simply with the Full-wave Bridge rectifier. The ripple does make sense
because the discharge of capacitor is what is being shown when the voltage drops, then when the voltage
goes high again this is because the Full-wave rectifier goes to it’s max voltage again. The ripple
amplitude we calculated for this part of the experiment was 22 micro F.
4.) Signal Diodes: This part of the experiment asked us to construct the following circuit shown below.
For this we needed to make a rectified differentiator using diodes driven with a square wave at 10kHz at
the function generators maximum output amplitude.
Below are the scope pictures we achieved through completing this part of the experiment.
From looking at the data we achieved from working with the scope you can see that in the original circuit
when connected produces a quick pulse. This can be seen in the first two pictures taken of the scope for
this part of the experiment. This actually doers make sense because the derivative of a square wave
happens to be just a pulse. The reason there are no negative bound pulses is because the diode filters out
all of the negatives. The 2.2k resistor serves as one of the main factors for setting the time constant of the
discharge of the pulse. The reason that when removing the resistor from the circuit that the discharge is so
slow is because the resistance and impedance are now being pulled straight from the scope. These
numbers are much larger than what we were originally using so the time constant was drastically
changed.
Conclusion
I feel very accomplished after finishing up this experiment. We were able to learn about the different
kinds of rectifiers and how they work. This was a very interesting topic to me because rectifiers are used
in order to convert AC into DC by changing the waves from positive and negative to just positive. The
utilization of diodes in these specific circumstances was very fascinating to me because this was
something, I had found myself wondering about up until we learned it in electronics class, and now I am
able to see construct a circuit used in order to accomplish this AC to DC change for myself.