College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Laboratory Experiment No. 2
Transistor Small Signal Amplifiers
Section:
CpE - 2204 (Group No. 1)
Names:
Abagon, Jarry Nash
Areta, Ralph Jan
Bacay, Marc Jian
Elomina, Isaac
Gupit, Carlos Ruben
Malubag, Rafael John
Submitted to: Engr. James Darrel Lara
Date: April 6, 2024
I.
Abstract
Three main objectives are being investigated in this experiment to learn more
about transistor circuit characteristics: determining input and output impedance,
interpreting the effects of source and load resistances, and measuring and
differentiating the gain under loaded and no-load conditions. The experiment aims to
improve understanding of transistor behavior and its implications for circuit design
through hands-on measurements and analysis. Decisions about impedance matching,
power transfer optimization, and circuit stability can be made with the help of the
study's insights.
II.
Introduction
The objective of this experiment is to thoroughly investigate transistor circuits,
focusing on their internal functionality and the variables influencing their effectiveness.
Three main goals have been established to direct the research.
The primary objective is to measure and fully understand a transistor amplifier's
gain in two different scenarios: when functioning as a no-load (with no external load)
and when connected to various loads. Analyzing the amplifier's ability to drive external
components and its performance under different load scenarios will elucidate its
functionality. Through this investigation, the researchers aim to gain insights into the
workings of the amplifier and its versatility in real-world applications.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Secondly, the researchers aim to accurately measure the transistor amplifier's
input and output impedance. This is crucial for maximizing the amplifier's efficiency and
ensuring smooth power transfer throughout the circuit. By precisely identifying these
impedance values, adjustments can be made to seamlessly integrate the amplifier with
other circuit components, thereby improving overall performance.
The overall objective is to deepen the comprehension of transistor circuits and
utilize this understanding to inform design choices, thereby enhancing their reliability
and performance in real-world applications. The ultimate goal is to grasp transistor
circuitry through comprehensive experimentation and analysis, thereby paving the way
for innovative developments in electronic engineering.
III.
Objectives
1. To measure and differentiate the no-load and loaded gain of a transistor circuit.
2. To measure the value of the input and output impedance of a transistor amplifier.
3. To interpret the effects of source and load resistances.
IV.
Materials / Tools / Equipment
1. Adjustable DC Power Supply
2. Function Generator
3. Resistors
4. 1N4001 Silicon Diode
5. Breadboard
6. Connecting Wires (Size #22)
7. Multimeter
8. Oscilloscope
9. Simulation Software (Multisim of Online Software)
V.
Procedures
a. Voltage Gain
i. Construct the circuit shown in Figure 1.1
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
ii.
iii.
v.
Connect a 10μF ceramic capacitor as a coupler capacitance.
Apply 5mV with frequency of 1 KHz sinusoidal input to the amplifier using a
function generator.
Measure the input and output voltage of the amplifier circuit using an
oscilloscope.
Using eq. 2.1, solve the voltage gain.
vi.
Repeat the process using the parameters in figure 1.2 and 1.3.
iv.
b. Input Impedance
i. Construct the circuit shown in Figure 1.1
ii. Connect a 10μF ceramic capacitor as a coupler capacitance.
iii. Obtain the output waveform using oscilloscope
iv. Apply 5mV with frequency of 1 KHz sinusoidal input to the amplifier using
function generator in series with 100Ω sense resistor (𝑅𝑠𝑒𝑛𝑠𝑒).
v.
vi.
Measure the source and input voltage of the transistor amplifier.
Compute the input current using eq. 2.2.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
vii.
Compute the input impedance using eq. 2.3.
viii.
Repeat the process using the parameters in figure 2.2 and 2.3.
c. Output Impedance
i. Construct the circuit shown in Figure 1.1
ii. Connect a 10μF ceramic capacitor as a coupler capacitance.
iii. Short out the input of the amplifier.
iv. Apply 5mV with frequency of 1 KHz sinusoidal input to the amplifier using
function generator in series with 100Ω sense resistor (𝑅𝑠𝑒𝑛𝑠𝑒).
v.
vi.
Measure the source and output voltage of the transistor amplifier.
Compute the output current using eq. 2.4.
vii.
Compute the output impedance using eq. 2.5.
viii.
Repeat the process using the parameters in figure 2.2 and 2.3.
d. Effects of Load and Source Resistance
i. Construct the circuit shown in figure 2.1.
ii. Connect a 10μF ceramic capacitor as a coupler capacitance.
iii. Connect a 1kΩ load resistor.
iv. Apply 5mV with frequency of 1 KHz sinusoidal input to the amplifier using a
function generator.
v. Measure the gain.
vi. Repeat the process for 2.2kΩ, 3.3kΩ, 5kΩ and 4.7kΩ load resistances.
vii. Remove the Load Resistor.
viii. Connect a 100Ω series resistance to the function generator.
ix. Measure the gain with respect to the input of the amplifier and with respect to
the source voltage.
x. Record your measurements.
xi. Repeat steps 7-10 of 220Ω, 330Ω, and 470Ω.
xii. Combine the different source and load resistances in your measurements
xiii. Record your measurements.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
VI.
Data and Results
In the following section, we will delve into the results and discussion stemming
from the laboratory experiment on Transistor Small Signal Amplifiers. The figures that
accompany our analysis showcase the schematics of the BJT Fixed Bias Circuit, BJT
Voltage Divider Bias Circuit, and JFET Emitter Bias Circuit. The analysis of the circuits
were done through the use of NI Multisim. Moreover, this analysis will rely on different
formulas in order to get certain values needed for the experiment like the voltage gain,
input impedance, and output impedance.
a. Voltage Gain
Figure 2.1.1 BJT Fixed Bias Circuit (Input Voltage)
Figure 2.1.2 BJT Fixed Bias Circuit (Output Voltage)
From the diagram provided, it is evident that oscilloscopes were employed to
monitor and measure the input and output voltages of the BJT Fixed Bias Circuit. The
input voltage was found to be 4.988mV, while the output voltage was measured at
1.078V.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 2.2.1 BJT Voltage Divider Bias Circuit (Input Voltage)
Figure 2.2.2 BJT Voltage Divider Bias Circuit (Output Voltage)
It can be inferred from the data presented in the diagram that oscilloscopes were
utilized to measure and document the input and output voltages of the BJT Voltage
Divider Bias Circuit. Specifically, the input voltage was measured at 4.991mV, while the
output voltage registered at 449.856mV.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 2.3.1 JFET Emitter Bias Circuit (Input Voltage)
Figure 2.3.2 JFET Emitter Bias Circuit (Output Voltage)
By closely examining the schematic, one can discern the utilization of
oscilloscopes to track and document the input and output voltages of the JFET Emitter
Bias Circuit. The input voltage was measured at 4.986mV, while the output voltage was
recorded at 18.882mV.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 2.4.1 Manual Computations for Voltage Gain
The voltage gain, calculated as Av = Vout/Vin, represents the amplification factor
achieved by simulation in Multisim. For the given input voltages of 4.988mV, 4.991mV,
and 4.986mV, corresponding to output voltages of 1.078V, 449.856mV, and 18.882mV,
respectively, the resulting voltage gains were found to be 216.119, 90.133, and 3.787.
This indicates how much the circuit amplifies the input signal. In practical terms, a
voltage gain means that the output voltage is substantially larger than the input voltage,
highlighting the circuit's amplification capability.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
b. Input Impedance
Figure 3.1.1 BJT Fixed Bias Circuit (Voltage Source)
Figure 3.1.1 BJT Fixed Bias Circuit (Input Voltage)
From the data provided, it is evident that oscilloscopes were utilized to measure
and capture the voltage source and input voltage of the BJT Fixed Bias Circuit. Notably, a
100Ω sense resistor is observed to be in series with the function generator. The voltage
source is recorded at 4.983mV, while the input voltage is measured at 4.580mV.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 3.2.1 BJT Voltage Divider Bias Circuit (Voltage Source)
Figure 3.2.2 BJT Voltage Divider Bias Circuit (Input Voltage)
It can be observed from the given figures that oscilloscopes were utilized to
measure and acquire the voltage source and input voltage of the BJT Voltage Divider
Bias Circuit. Furthermore, it can be noted that a 100Ω sense resistor is in series with the
function generator. The voltage source is measured at 4.992mV, while the input voltage
is measured at 4.836mV.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 3.3.1 JFET Emitter Bias Circuit (Voltage Source)
Figure 3.3.2 JFET Emitter Bias Circuit (Input Voltage)
Analyzing the given figures, it is apparent that oscilloscopes were utilized to
measure and obtain the voltage source and input voltage of the BJT Voltage Divider Bias
Circuit. Additionally, the inclusion of a 100Ω sense resistor in series with the function
generator is observed. The voltage source is measured at 4.996mV, while the input
voltage registers at 4.842mV.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 3.4.1 Manual Computations for Input Impedance
In Multisim, Oscilloscopes within a BJT Fixed Bias Circuit were utilized to measure
the Input Impedance. Employing manual computation, the Input Current (Ii) was
determined using the formula Ii = (Vsource - Vin) / Rsense, where Vsource denotes the
source voltage, Vin represents the input voltage, and Rsense indicates the resistor sense.
The resulting input current values were found to be 4.030uA, 1.560uA, and 1.540uA,
respectively, based on the given values: Vsource (4.983mV, 4.992mV, 4.996mV), Vin
(4.580mV, 4.836mV, 4.842mV), and Rsense (100, 100, 100). Additionally, the Input
Impedance was determined to be 1136.476, 3100, and 3144.156, respectively, reflecting
the resistance that the circuit presents to the input signal source.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
c. Output Impedance
Figure 4.1.1 BJT Fixed Bias Circuit (Voltage Source)
Figure 4.1.1 BJT Fixed Bias Circuit (Output Voltage)
Considering the given schematic, it's evident that oscilloscopes were employed
to measure and obtain the voltage source and input voltage of the BJT Fixed Bias Circuit.
Additionally, it's worth noting that a 100Ω sense resistor is in series with the function
generator, resembling the input impedance. The voltage source is measured at 4.992mV,
while the output voltage is observed at 1.002mV.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 4.2.1 BJT Voltage Divider Bias Circuit (Voltage Source)
Figure 4.1.1 BJT Voltage Divider Bias Circuit (Output Voltage)
From the given figures, it can be observed that oscilloscopes were employed to
measure and obtain the voltage source and input voltage of the BJT Voltage Divider Bias
Circuit. Additionally, the inclusion of a 100Ω sense resistor in series with the function
generator, akin to the input impedance, is notable. The voltage source is measured at
4.976mV, while the input voltage is recorded at 436.5596mV.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 4.3.1 JFET Emitter Bias Circuit (Voltage Source)
Figure 4.3.1 JFET Emitter Bias Circuit (Output Voltage)
It can be concluded from the given figures that oscilloscopes were employed to
measure and capture the voltage source and input voltage of the BJT Voltage Divider
Bias Circuit. Furthermore, it is evident that a 100Ω sense resistor is present in series with
the function generator, mirroring the input impedance.sniphe voltage source is noted at
4.986mV, while the input voltage is observed at 18.862mV.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 4.4.1 Manual Computations for Output Impedance
In Multisim, Oscilloscopes within a BJT Fixed Bias Circuit were utilized to measure
the Output Impedance. Proceeding with manual computation, the Output Current (Io)
was determined using the formula Io = (Vsource - Vo) / Rsense, where Vsource denotes
the source voltage, Vo represents the output voltage, and Rsense indicates the resistor
sense. The resulting output current values were found to be 4.3062mA, 0.13876mA,
and 9.97008mA, respectively, based on the given values: Vsource (4.976mV, 4.986mV,
4.992mV), Vo (436.596mV, 18.862mV, 1002mV), and Rsense (100, 100, 100).
Additionally, the Output Impedance was determined to be 100.3878, 135.9325, and
100.5007.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
d. Effects of Load and Source Resistance
In this section, several load resistors were connected individually to the BJT Fixed
Bias Circuit ranging from 1kΩ to 5kΩ. Additionally, this section also includes resistors
being connected in series with the function generator which range from 100Ω to 470Ω.
Furthermore, the input and output voltages as well as the voltage gain were measured.
The procedure was repeated for various source resistors and combinations of load and
source resistance.
Figure 5.1.1 Measured Input and Output Voltage with 1kΩ Load Resistance
Figure 5.1.2 Measured Input and Output Voltage with 2.2kΩ Load Resistance
Figure 5.1.3 Measured Input and Output Voltage with 3.3kΩ Load Resistance
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 5.1.4 Measured Input and Output Voltage with 5kΩ Load Resistance
Figure 5.1.5 Measured Input and Output Voltage with 4.7kΩ Load Resistance
In the simulation depicted in the figures, an oscilloscope was utilized to measure
and acquire the input voltage and output voltage for the BJT Fixed Bias Circuit.
Proceeding in manual computation, to get the Voltage Gain (𝐴𝑣) we used the formula
located in eq. 1. which is Voltage Gain (𝐴𝑣) is equal to Output Voltage (𝑉𝑜𝑢𝑡) over Input
Voltage (𝑉𝑖𝑛) (𝐴𝑣 = 𝑉𝑜𝑢𝑡/𝑉𝑖𝑛).
Load Resistance
Input Voltage (𝑉𝑖𝑛)
Output Voltage (𝑉𝑜𝑢𝑡) Voltage Gain (𝐴𝑣)
1kΩ
𝑉𝑖𝑛 = 4.989mV
𝑉𝑜𝑢𝑡 = 286.294mV
𝐴𝑣 = 57.385
2.2kΩ
𝑉𝑖𝑛 = 4.992mV
𝑉𝑜𝑢𝑡 = 475.365mV
𝐴𝑣 = 95.225
3.3kΩ
𝑉𝑖𝑛 = 4.992mV
𝑉𝑜𝑢𝑡 = 580.315mV
𝐴𝑣 = 116.249
5kΩ
𝑉𝑖𝑛 = 4.992mV
𝑉𝑜𝑢𝑡 = 686.329mV
𝐴𝑣 = 137.486
4.7kΩ
𝑉𝑖𝑛 = 4.992mV
𝑉𝑜𝑢𝑡 = 671.388mV
𝐴𝑣 = 134.493
Table 1. Measured Voltage Value and Voltage Gain
From the table we can see that it shows a pattern of rising voltage gain with
increasing load resistance levels. To be more specific, as the load resistance grows from
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
1k to 5k, so does the voltage gain. Thus we can assume that the voltage gain is directly
proportional to the load resistance in a BJT Fixed Bias Circuit.
Figure 5.2.1 Measured Values with 100Ω Source Resistance (Input Amplifier)
Figure 5.2.2 Measured Values with 220Ω Source Resistance (Input Amplifier)
Figure 5.2.3 Measured Values with 330Ω Source Resistance (Input Amplifier)
Figure 5.2.4 Measured Values with 470Ω Source Resistance (Input Amplifier)
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
From the given figures we can see in the simulation that an oscilloscope was also
used in order to measure and obtain the input voltage and the output voltage with
respect to the input of the amplifier for the BJT Fixed Bias Circuit. However, in the
schematic the load resistor is removed and instead a source resistor connected.
Proceeding in manual computation, we also used the same formula in order to get the
voltage gain.
Figure 5.3.1 Measured Values with 100Ω Source Resistance (Source Voltage)
Figure 5.3.2 Measured Values with 220Ω Source Resistance (Source Voltage)
Figure 5.3.3 Measured Values with 330Ω Source Resistance (Source Voltage)
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Figure 5.3.4 Measured Values with 470Ω Source Resistance (Source Voltage)
It can be inferred from the simulation that an oscilloscope was utilized to
measure and record both the input and output voltages relative to the source voltage for
the BJT Fixed Bias Circuit. However, the schematic displayed the removal of the load
resistor, with a source resistor being incorporated instead. However, manual
computations proceeded using the same formula to derive the voltage gain.
Source
Resistance
Input Amplifier
𝑉𝑖𝑛
𝑉𝑜𝑢𝑡
100Ω
4.577mV
220Ω
Source Voltage
𝐴𝑣
𝑉𝑖𝑛
𝑉𝑜𝑢𝑡
𝐴𝑣
982.167mV
214.588
4.992mV
980.516mV
196.417
4.167mV
907.621mV
217.812
4.992mV
907.621mV
181.815
330Ω
3.853mV
848.113mV
220.118
4.992mV
848.113mV
169.894
470Ω
3.519mV
782.331mV
222.316
4.992mV
782.331mV
156.717
Table 2 Combined Value and Voltage Gain of Input Amplifier and Source Voltage
From the data provided in the table, it's apparent that there's a diverse trend
observed in voltage gain values concerning both the amplifier's input and the source
voltage. When considering voltage gain with respect to the amplifier's input, it becomes
evident that an increase in source resistance corresponds to higher voltage gain values.
However, when measuring voltage gain in relation to source voltage, raising the source
resistance value reduces the voltage gain. With this we can say that the voltage gain is
directly proportional to the source resistance with respect to the input amplifier, on the
other hand the voltage gain is inversely proportional to the source resistance with
respect to the source voltage.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
VII.
Conclusion
Abagon, Jarry Nash R.
The experiment thoroughly investigated transistor-based amplification circuits,
exploring diverse circuit topologies and biasing techniques to understand their
functionality. A significant finding was the substantial impact of source and load
resistances on voltage gain: higher source resistance increased input gain, while
increased load resistance amplified overall gain. These results highlighted the crucial role
of resistance parameters in shaping transistor amplifier performance. Mastering these
relationships is essential for optimizing amplifier circuits across various applications,
allowing engineers to tailor designs to meet specific performance requirements
effectively. Overall, the experiment provided valuable insights into transistor behavior
and its implications for circuit design and optimization.
Hands-on experimentation provided practical insights into transistor circuit
behavior, crucial for future electronic engineering endeavors. This tactile approach
demonstrated how changes in circuit components directly affect amplifier performance.
Mastery of these fundamental concepts empowers engineers to make informed
decisions in circuit design and optimization, fostering the development of robust
electronic systems. The insights gained from this experiment form a solid foundation for
advancing our understanding of transistor behavior and its applications in electronic
design.
Areta, Ralph Jan L.
This experiment using transistors as small signal amplifiers provided useful
information about the functionality and performance of these amplification circuits.
Analysis revealed that different circuit topologies incorporating transistors exhibit a
range of key properties that influence signal amplification. It provides an understanding
of the significance of biasing techniques in improving amplifier performance and
stability.
The measured voltage gain patterns with respect to source and load resistance in
a BJT Fixed Bias Circuit provide useful information on amplifier behavior. As source
resistance increases, so does the voltage gain with respect to the amplifier's input,
thanks to the voltage division principle. This happens because increased source
resistance causes the source's total impedance to increase, resulting in a larger voltage
drop across the load impedance and hence higher voltage gain. When evaluating voltage
gain in relation to the source voltage, increasing the source resistance reduces the
voltage gain by limiting the amount of voltage available to the amplifier.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
On the other hand, regarding load resistance, the voltage gain rises as load
resistance levels increase. This phenomenon is attributed to the decrease in current
flowing through the load as load resistance increases, resulting in a smaller voltage drop
across the load resistor. Consequently, a larger portion of the output voltage is
developed across the load, leading to an increase in voltage gain. Understanding these
relationships between source resistance, load resistance, and voltage gain is crucial for
designing and optimizing amplifier circuits for various applications.
Bacay, Marc Jian B.
This experiment on Transistor Small Signal Amplifiers provided valuable insights
into transistor behavior and its impact on circuit performance. We observed that varying
source and load resistances affect voltage gain, with increasing source resistance
correlating to higher gain at the amplifier's input, while higher load resistance leads to
increased voltage gain. Understanding these relationships is crucial for optimizing
amplifier circuits for various applications.
Through hands-on experimentation, we deepened our understanding of
transistor circuits, laying a solid foundation for future electronic engineering endeavors.
This practical approach allowed us to observe firsthand how different circuit
components and configurations affect transistor amplifier performance. By mastering
these concepts, we can make informed decisions in circuit design and optimization,
ensuring reliable and efficient electronic systems.
Elomina, Isaac C.
This experiment, utilizing transistors as small signal amplifiers, has yielded
valuable insights into the functionality and performance of such amplification circuits.
Through analysis, it has been determined that different circuit topologies incorporating
transistors exhibit a spectrum of crucial properties affecting signal amplification.
Additionally, it underscores the significance of biasing techniques in enhancing amplifier
performance and stability.
Conversely, concerning load resistance, voltage gain escalates with increasing
load resistance levels. This phenomenon arises from the reduction in current flowing
through the load as load resistance increases, resulting in a diminished voltage drop
across the load resistor. Consequently, a larger portion of the output voltage is
developed across the load, leading to an upsurge in voltage gain. Mastery of these
relationships between source resistance, load resistance, and voltage gain is
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
indispensable for the design and optimization of amplifier circuits across various
applications.
Gupit, Carlos Ruben A.
The assessment of an amplifier's amplifying ability through the ratio of output to
input is valuable due to its capability to enhance signal amplitude, known as gain. Gain
encompasses various unit combinations such as power, voltage, or current ratios. Input
and output impedance, representing the proportion of voltage to current flowing
through an amplifier's terminals, are significant factors influenced by source supply and
load impedance, respectively. Load impedance plays a critical role in circuit behavior
under varying conditions, affecting maximum load transmission and time constants in
charging and discharging. Employing Multisim for circuit analysis yields approximate
values, serving as initial estimations for manual calculations to verify consistency
between Multisim data and manual solutions. Through this combined approach,
objectives are met in demonstrating the functionality of a Transistor Small Signal
amplifier within the specified circuit.
Malubag, Rafael John M.
In this experiment, we explored how transistors act as small signal amplifiers,
which provided us with useful insights into how these circuits work and perform. By
looking closely at different circuit setups using transistors, we learned about the various
factors that affect signal amplification. We also learned how important it is to set up the
transistors correctly to make sure the amplifier works well and stays stable. We found
some interesting patterns when we looked at how voltage gain changes with different
source and load resistances in a BJT Fixed Bias Circuit. When we increased the source
resistance, we noticed that the voltage gain at the amplifier's input also increased. This
is because more source resistance means more impedance, which leads to a bigger
voltage drop across the load and, therefore, higher voltage gain.
Conversely, when we looked at voltage gain concerning the source voltage, we
found that increasing the source resistance reduced the voltage gain. This is because
more source resistance limits the amount of voltage available to the amplifier. When it
came to load resistance, we saw that as load resistance increased, so did voltage gain.
This happened because as load resistance went up, less current flowed through the load,
resulting in a smaller voltage drop across the load resistor. As a result, more of the
output voltage was developed across the load, leading to higher voltage gain.
College of Engineering – Department of Electrical Engineering
ECE 421 - Electronic Circuits: Devices and Analysis
Understanding these relationships between source resistance, load resistance, and
voltage gain is important for designing amplifier circuits for different uses.