1. Operational amplifier applications

2. Summing amplifier

3. Instrumentation amplifier

4. Integrating amplifier

5. Some sensors output a current rather than a voltage
Some sensors output a current rather than a voltage. The most common sensor of this type is the photodiode which has a current output proportional to the amount of light shining on it. The purpose of the signal conditioning circuitry is to convert the current output of the sensor to a voltage.
Photocell Connected to a Current Amplifier

6. Differentiating amplifier

7. OPAMP in Non-linear configurations
Precision rectifier
Although there are some limitations, this super diode circuit behaves like an ideal diode for the load RL

8. OPAMP in Non-linear configurations
Precision rectifier (Improved Circuit)
transfer characteristic

9. Peak detector
With little modifications basic precision rectifier can be used also for detecting peak levels of signal. In the following circuit a capacitor keeps the peak voltage level of signal and switch can be used for resetting detected level.

10. OPAMP in Non-linear configurations
Logarithmic output

11. OPAMP in Non-linear configurations
Exponential configuration

12. The effect of using a Schmitt trigger (B) instead of a comparator (A).

13. Schmitt trigger
Link to Simulation

14. Schmitt trigger with inverting hysteretic switching characteristic
Link to Simulation 1 2
switching thresholds are:

15. A practical Schmitt trigger configuration

16. Use as an oscillator 1 2