This circuit can be used as a shield for touch control. The circuit can use any common FET like the BF245 and should never be powered by a source without a transformer.
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...