7. Circuits with operational amplifiers

Note

This is part of the LabsLand Electronics laboratory documentation for educators using VISIR. If you want to use this lab in class, check Use this laboratory in class.

Thanks to the Analog Electronics remote laboratory also it can be experienced with circuits more complex, including integrated circuits. They are listed some examples that can be implemented using operational amplifiers, specifically the U741, whose scheme appears in the figure below:

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Fig. 7.1 UA741 integrated circuit

7.1. Non-inverting Operational Amplifier Configuration

Fig. 7.1.1 shows the electronic scheme of the UA741 op-amp operating as non-inverter amplifier. To check the effect of amplification, it is possible to change the resistance placed in the branch of feedback to take the values shown in Fig. 7.3.1.

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Fig. 7.1.1 Op-amp operating as non-inverter amplifier

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Fig. 7.1.2 Implementation of op-amp operating as non-inverter amplifier, using 100kΩ | Download this circuit

Remember that the function generator generates a signal of double amplitude that sets it in its front panel. If you need a different configuration, let us know.

Very important: feed the circuit with + 15VDC -15VDC for correct operation.

7.2. Inverting amplifier

Fig. 7.2.1 shows the UA741 op amp electronic scheme working as inverter amplifier. To check the effect of amplification, it is possible to change the resistance placed in the branch of feedback to take the values shown in Fig. 7.3.1.

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Fig. 7.2.1 Op-amp operating as inverter amplifier

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Fig. 7.2.2 Implementation of op-amp operating as inverter amplifier, using 100kΩ | Download this circuit

7.3. Op-amp Differentiator circuit

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Fig. 7.3.1 Op-Amp Differentiator circuit

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Fig. 7.3.2 Op-amp Differentiator circuit implementation, being R=100kΩ and a triangle input signal | Download this circuit

7.4. Op-amp Integrator circuit

Next figure shows the UA741 working as integrator amplifier. As in the previous circuits, the resistor connected on the feedback branch, can adopt the values shown at Fig. 7.4.1.

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Fig. 7.4.1 Op-Amp Integrator circuit

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Fig. 7.4.2 Op-amp integrator circuit implementation, being R=100kΩ and a square input signal | Download this circuit

7.5. Op-amp Comparator circuit

Next figure shows the UA741 working as comparator. As in the previous circuits, the resistor connected on the feedback branch, can adopt the values shown at Fig. 7.5.1.

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Fig. 7.5.1 Op-Amp comparator circuit

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Fig. 7.5.2 Op-amp comparator circuit implementation | Download this circuit

That’s all in Operational Amplifiers. Continue in Circuits with transistors.