Operational Amplifier Equations For Circuit Design
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Introduction
An operational amplifier (op-amp) is an analogue circuit block that takes a differential voltage input and produces a single-ended voltage output. How to solve op-amp circuits? Look at the following op-amp equations by several main operational amplifier applications circuit.
An operational amplifier has two input pins and one output pin. Its applications in a host of different circuits where their attributes of gain, input impedance, output impedance, differential input and so on. The major op-amp formulas used to calculate are shown as follow:
Fig 1. Voltage Follower
Note: Buffer High Impedance Signal and Low Impedance Load
Fig 2. In-phase Op-Amp
Note: In-phase Signal Amplification
Fig 3. Reversed-phase Op-Amp
Note: Amplify and Invert Input
Fig 4. Voltage Subtractor, Differential Amplifier
Note: Amplify the voltage difference and suppress the common-mode voltage
Fig 5. Voltage Adder
Note: Summation of Adding Voltage Values
Fig 6. Low-pass Filter, Integrator
Note: Limit Signal Bandwidth
Fig 7. High-pass Filter, Differentiator
Note: Eliminate DC, Amplify AC Signal
Fig 8. Differential Amplifier
Note: Drive Differential Signal to Analog-to-Digital Converter From A Differential or Single-ended Signal Source
Fig 9. Instrumentation Amplifier
Note: Amplify the Low-Level Difference Signal and Suppress the Common Mode Signal
Fig 10. Single-State Op-Amp Noise
Note:
RTO NOISE=NG×RTI NOISE
RTI=Converted to the Input
RTO=Converted to the Output
Decibel Formula (equivalent impedance)
Johnson-Nyquist Noise Formula
Ohm's Law (DC circuit)
Fig 11. Closed-loop Frequency Response (voltage feedback amplifier)
Resistance Formulas
Reactance Formulas
Impedance Formulas (in series)
Note:
RL in series
RC in series
LC in series
RLC in series
Voltage and Impedance Formulas (parallel connection)
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