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The Operational Amplifier

·106 words·1 min·
Stefano
Author
Stefano

The Operational Amplifier
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The operational amplifier (op-amp) is one of the most important components in analog electronics. It amplifies the difference between two input voltages with very high gain.

Op-amp symbol
Operational amplifier symbol - Public domain

Golden Rules (ideal)
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  1. No current flows into the inputs
  2. \(V^+ = V^-\) (virtual short)

Inverting Amplifier
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\(V_o = -\frac{R_f}{R_1} \cdot V_{in}\) — output is inverted and amplified.

Non-Inverting Amplifier
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\(V_o = \left(1 + \frac{R_f}{R_1}\right) \cdot V_{in}\) — output keeps the same sign.


Conclusion
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The op-amp is the building block of analog electronics. With just a few resistors, you can build amplifiers, filters, oscillators and much more.