Operational amplifier

applications

Summing amplifier

Instrumentation amplifier

Integrating amplifier

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

Differentiating amplifier

OPAMP in Non-linear configurations

Precision rectifierAlthough there are some limitations, this super diode circuit behaves like an ideal diode for the load RL

OPAMP in Non-linear configurations

Precision rectifier (Improved Circuit) transfer characteristic

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.

Logarithmic output

OPAMP in Non-linear configurations

Exponential configuration

OPAMP in Non-linear configurations

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

B

A

Schmitt trigger

Link to Simulation

Schmitt trigger with inverting hysteretic switching characteristic

switching thresholds are:

1Link to Simulation

2

A practical Schmitt trigger configuration

Use as an oscillator

1 2