This interface shield circuit is from the 1983 Intersil Databook. The components used are uncommon today. ADCs are low-cost digital converters. The power source voltage must be 5 V.
The figure shows three circuits for using headphones in amplifiers with speakers that do not have...
In this charger, the charging current is basically limited by the LEDs. The transformer is a low...
This configuration is from an old integrated circuit manual. The circuit can be applied to modern...