This shield circuit for lamps and other charges was found in a Popular Electronics from the 90's. The MOSFET admits equivalent according to the charging current.
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...