Analysing Op Amp Circuit with a Photo diode

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SUMMARY

The discussion focuses on the role of bypass capacitors in an op-amp circuit utilizing a photodiode. The circuit amplifies a blinking signal, with the op-amp configured for negative feedback to control gain. Bypass capacitors are essential for filtering out noise and ripple from power supplies, particularly in high-gain applications. The maximum output voltage of the op-amp is limited to ±12V, emphasizing the importance of clean power for optimal performance.

PREREQUISITES
  • Understanding of operational amplifier (op-amp) fundamentals
  • Knowledge of negative feedback principles in circuit design
  • Familiarity with photodiode operation and signal processing
  • Basic concepts of power supply noise and ripple effects
NEXT STEPS
  • Research the function and types of bypass capacitors in electronic circuits
  • Study the impact of power supply noise on op-amp performance
  • Learn about different configurations of op-amps and their applications
  • Explore advanced techniques for signal amplification in high-gain circuits
USEFUL FOR

Electronics students, circuit designers, and engineers working with op-amps and photodiodes, particularly those interested in improving circuit performance and noise reduction.

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For a lab we built the following circuit.

DiodeCircuit.jpg

Our photo diode was receiving a blinking signal which our op amp made visible on a DVM.

I do not understand the purpose of the capacitors attached to the power rail.
So far I understand how negative feed back with the Rf resistor controls the amount of gain. Without negative feed back the op amp would produce near infinite gain. The maximum voltage that can come out of the op amp is + or - 12V but about the capacitors I am at a loss.
Any help would be appreciated.
 
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If you were using 12 volt batteries for your power supply the capacitors wouldn't serve any purpose. However power supplies connected to the mains have ripple and other noise, particularly switching supplies. With high gain circuits these imperfections are amplified and degrade the output. Those capacitors help clean up the power supply for the circuit.
 
Thank you skeptic2.

I just came across the word bypass capacitors that must be it.
 

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