Found in a Maxim publication from the 90s, this circuit generates signals from 10 to 25 kHz with a THD better than -80 dB. The circuit makes use components of the time.
This filter for the 300 Hz to 3 kHz range was found in an American documentation from the 90's....
The battery is charged by the photocell that keeps the low consumption beacon in the dark. The...
This is the typical circuit of an FET amplifier stage in the common source configuration. The circuit is...