Non-Inverting Unity Gain Amplifier Experiment Report, Lab Reports of Electronic Circuits Design

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Fall 2025 | EECS 70LB

Experiment:

NON-INVERTING UNITY GAIN AMPLIFIER

Introduction/Objective

The purpose of this experiment was to study the behavior and performance of a non-inverting

voltage follower amplifier using an operational amplifier. The goal of this lab was to verify the

theoretical relationship between input and output voltages when the amplifier is configured for

unity gain, and to observe how the circuit maintains signal amplitude while providing high input

impedance and low output impedance. This experiment also provided practical experience in

operating common electronic test equipment such as the oscilloscope, function generator,

multimeter, and DC power supply.

The main objectives were to design and build a non-inverting voltage follower circuit, observe

that the output follows the input without any phase inversion, and confirm that the voltage gain

remains approximately one across varying input amplitudes and frequencies. Additionally, the

experiment emphasized the importance of proper feedback connections, power supply

configuration, and understanding op-amp limitations such as output saturation and bandwidth

effects. Overall, this lab reinforced fundamental op-amp principles and enhanced skills in circuit

construction, measurement, and signal analysis.

Methodology/Procedure

List of Equipment

• μA741 Operational Amplifier (single IC)
• Resistors: 1𝑘Ω, 2. 2𝑘Ω, 4. 7𝑘Ω, 10𝑘Ω
• Breadboard
• Connecting wires
• Dual DC Power Supply (± 10 𝑉)
• Function generator (AFG)
• Digital storage oscilloscope (DSO)
• Digital multimeter
• BNC Cables and oscilloscope probes

Procedure

Circuit Assembly:

A non-inverting unity gain amplifier (voltage follower) was built using the μA741 op-amp on a

breadboard. The input signal was applied to the non-inverting terminal, while the inverting

terminal was directly connected to the output to provide unity gain feedback. The circuit was

powered by ±10 V DC supplies.

Signal Configuration and Measurement:

Sinusoidal input signals of varying amplitudes (200–2050 𝑚𝑉 ) at 50 kHz and 500 kHz were

𝑝𝑝

applied. Input and output waveforms were observed on a digital oscilloscope, and 𝑉 , , and

𝑝𝑝

𝑟𝑚𝑠

frequency was recorded. Voltage gain and gain in decibels were calculated to assess amplifier

performance.

Analysis and Verification:

Measured voltage gain remained near 1 , with the output in phase with the input. Minor

deviations were due to op-amp non-idealities, confirming the amplifier buffers the input while

maintaining high input and low output impedance.

Figure 2: Finished Circuit Setup with 𝑅 and

𝑓

𝑖

**Data/Results

Frequency (HZ)**

INPUT OUTPUT

Voltage Gain Voltage Gain Vpp (mV) Vrms (mV) Vpp(mV) Vrms (mV) (db) 1 500,000 222 69.18 231.32 66.4 1.959814975 5. 2 500,000 406.36 138.97 391 118.67 1.853925308 5. 3 500,000 600.14 206.69 444.17 138.46 1.669892109 4. 4 500,000 768.9 264.72 470.9 150.04 1.566787549 3. 5 500,000 998.2 346.02 485.3 168.05 1.485665568 3. 6 500,000 1107 1116 484 183.68 0.4372177055 -7. 7 500,000 1407 489.15 489.15 208.8 0.3476545842 -9. 8 500,000 1616 557.15 497.3 232.32 0.3077351485 -10. 9 500,000 1810 625.5 500.3 257.7 0.2764088398 -11. 10 500,000 2000 695.57 506.5 286.7 0.25325 -11. 11 50,000 213 70.72 216 70.95 1.014084507 0. 12 50,000 420 142.3 418 142.6 0.9952380952 -0. 13 50,000 621 213.67 619 214.02 0.9967793881 -0. 14 50,000 822.05 284.32 822.5 285.07 1.000547412 0. 15 50,000 1002 355.72 1023 356.58 1.020958084 0. 16 50,000 1226 427.22 1229 428.22 1.002446982 0. 17 50,000 1451 499.44 1430 499.84 0.9855272226 -0. 18 50,000 1650 570.08 1644 568.9 0.9963636364 -0. 19 50,000 1849 640 1840 638.55 0.9951325041 -0. 20 50,000 2051 711.8 2044 710.04 0.9965870307 -0.

Table. 1 Performance of a Non-Inverting Unity Gain Amplifier at Varying Input

Amplitudes and Frequencies

The table shows input and output measurements for the voltage follower across different signal

amplitudes and frequencies. The output remains in phase with the input, and the measured

voltage gain stays close to unity, confirming proper buffering and linear operation of the

amplifier.

Figure 5: Input and output waveforms for 500, 000𝐻𝑧 and𝑉𝑝𝑝 = 2000𝑚𝑉

For 500 kHz and 2000 mVpp, the output remains in phase with the input, verifying the amplifier

buffers higher amplitude signals without distortion.

Figure 6: Input and output waveforms for 50, 000𝐻𝑧 and𝑉

𝑝𝑝

At 50 kHz and 1002 mVpp, the voltage follower continues to exhibit unity gain and accurate

phase tracking, consistent with expected behavior.