Circuit Construction - 6.4.2

Key Concepts

• Op-Amp Power: Always connect dual power supplies correctly to the Op-Amp before any signal connections.

• Feedback Loop: The path from output through R1 to the inverting input, and R2 from inverting input to ground, forms the feedback loop.

• Voltage Divider: The R1-R2 network acts as a voltage divider, determining the feedback factor.

• Input Application: Input signal always goes to the non-inverting terminal for this configuration.

• Pre-Power Check: Essential to avoid damaging the sensitive Op-Amp.

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• Examples

• LM741 Pinout: When placing an LM741, you'd note that pin 7 is +Vcc, pin 4 is -Vcc, pin 2 is Inverting Input, pin 3 is Non-inverting Input, and pin 6 is Output. Your wiring must match these physical pins.

• Resistor Placement: If you choose R1 = 9 kΩ and R2 = 1 kΩ for a gain of 10, you would connect the 9 kΩ resistor between pin 6 and pin 2, and the 1 kΩ resistor between pin 2 and the ground rail.

• Input Connection: Your function generator's output lead would connect to pin 3 of the LM741.

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• Flashcards

• Term: Op-Amp Power Supply

• Definition: Requires precise connection of +Vcc, -Vcc, and Ground to the correct pins for the Op-Amp to function.

• Term: Non-inverting Input (+)

• Definition: The Op-Amp terminal where the primary input signal is applied in a non-inverting amplifier configuration.

• Term: Feedback Resistors (R1, R2)

• Definition: The two resistors that form a voltage divider to sample the output and feed a fraction back to the inverting input.

• Term: Decoupling Capacitors (Op-Amp)

• Definition: Small capacitors placed near Op-Amp power pins to reduce noise and improve stability.

• Term: Pre-Power Verification

• Definition: The critical step of visually and/or electrically checking all connections before applying power to prevent damage.

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• Memory Aids

• "O.P. P.O.W.E.R.": Op-Amp Pins, Power Orientation With Exact Resistors (R1 & R2).

• "Feedback Loop = Circle": The signal goes out of the Op-Amp and circles back to the input through the resistors.

• "Non-inverting = No Inversion": The output waveform will look just like the input, just amplified.

Examples & Applications

Memory Aids

Interactive tools to help you remember key concepts

Glossary