Practical Name:
To design an inverting amplifier using the OpAmp 741 and determine its gain.
Aim:
To design and implement an inverting amplifier circuit using operational amplifier IC 741 and to calculate its voltage gain.
Apparatus Required:
-
Operational Amplifier IC 741
-
Resistors (R₁ and Rf of suitable values)
-
Breadboard
-
DC Dual Power Supply (+12V and -12V)
-
Signal Generator
-
Cathode Ray Oscilloscope (CRO) or Digital Oscilloscope
-
Connecting Wires
Theory:
An inverting amplifier is a basic op-amp configuration where the input signal is applied to the inverting terminal through a resistor, and the non-inverting terminal is grounded. The feedback resistor (Rf) connects the output to the inverting input. The voltage gain of an inverting amplifier is given by:
The negative sign indicates that the output is 180° out of phase with the input.
Circuit Diagram:
(Insert a neat labeled diagram showing Op-Amp 741 in inverting mode with R₁ and Rf connected appropriately.)
Procedure:
-
Connect the circuit on a breadboard as per the given circuit diagram.
-
Apply a dual DC power supply (+12V and -12V) to the op-amp.
-
Connect a sine wave signal (e.g., 1 kHz, 1V peak) from the signal generator to the input terminal via resistor R₁.
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Observe the output waveform on the CRO.
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Measure the input and output voltage amplitudes.
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Calculate the voltage gain using the formula:
-
Repeat the experiment with different resistor values to verify the gain formula.
Observations:
| S. No. | Input Voltage (V<sub>in</sub>) | Output Voltage (V<sub>out</sub>) | R₁ (kΩ) | R<sub>f</sub> (kΩ) | Calculated Gain (A<sub>v</sub>) | Theoretical Gain (-Rf/R₁) |
|---|---|---|---|---|---|---|
| 1 | 0.5 V | -2.5 V | 1 | 5 | -5.0 | -5 |
| 2 | 0.5 V | -1.0 V | 2 | 2 | -2.0 | -1
|
| … | … | … | … | … | …\
|
…
|
Calculations:
For example, if R₁ = 1 kΩ and R<sub>f</sub> = 5 kΩ:
If input voltage = 0.5V, then output voltage = -2.5V (verified on CRO).
Result:
The inverting amplifier was successfully designed and implemented using IC 741. The observed gain values matched the theoretical values, confirming the correct operation of the circuit.
Conclusion:
The inverting amplifier circuit based on Op-Amp 741 amplifies the input voltage with a phase shift of 180°, and the gain depends on the resistor ratio (Rf/R₁). The experiment verifies the theoretical gain formula and demonstrates the basic working of an inverting op-amp amplifier.
Precautions:
-
Ensure all connections are made correctly before switching on the power supply.
-
Use resistors with accurate values to get precise gain.
-
Avoid short circuits by properly checking connections on the breadboard.
-
Use proper grounding for the op-amp and CRO to avoid signal noise.
BSc 2nd Year Chemistry Major 1 Important Questions 2025 —
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“नीम के पत्तों में छिपा है एंटीबैक्टीरियल गुणों का राज!”
क्या आप जानते हैं कि नीम (Azadirachta indica) के पत्ते न केवल स्वास्थ्य के लिए लाभकारी हैं, बल्कि बैक्टीरिया को भी मात देने की ताकत रखते हैं?
यह शोध, नीम के पत्तों से प्राप्त यौगिकों के प्रभावी एंटीबैक्टीरियल गुणों की गहरी जानकारी प्रदान करता है।
Dissertation Topic: “Neem (Azadirachta indica) के पत्तों से प्राप्त यौगिकों का एंटीबैक्टीरियल गुणों के लिए विश्लेषण”
यह शोध न केवल रसायन विज्ञान के क्षेत्र में नई जानकारी प्रस्तुत करता है, बल्कि प्राकृतिक उपचारों को वैज्ञानिक प्रमाणों के साथ जोड़ता है।
क्या आप भी नीम के गुणों पर आधारित नये उपचारों में रुचि रखते हैं?
यह Dissertation आपके ज्ञान को नई दिशा दे सकता है।
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