The presented circuit makes use of a common operational amplifier that must be powered by a symmetrical source. R resistors from 10k to 1M determine the gain and compression of the signal.
In the figure we have a simple way to produce tone in a piezoelectric transducer. The frequency depends...
This absolute value amplifier was found in a 90's EDN. Equivalent amplifiers can be used. The...
The integrated circuit used in this configuration for noise reduction on FM radios is not common...